Unplug it from the monitor and the a/c and disconnect network cable. Open it up .. maybe something as simple as a loose wire or loose card. I might unplug and reconnect all the sfuff to see if I get lucky. Only take 30 or so minutes.

Unless power surge, 2yrs is kind of soon to die.
Local computer shop most likely could change to a standard motherboard and use your cpu & memory.. bare motherboards are under 100 dollars cost to him and he might have one he would love to sell gathering dust. So the question might be,, what will he charge in labor and supplies.. is it worth it ? Sometimes its cheaper to just buy a new budget tower - that will probably be faster than what you had with win8 and slave your hard drive in it.

Lenovo call that model an "ultra small desktop". I could not find a case size but with that designation perhaps it has a custom sized motherboard and therefore not replaceable? Normal ATX motherboards are about 12 x 9 and microATX about 9.5 x 9.5

What do you hear running? Is there a single BIOS beep as it starts? According to this Youtube 30 second video you should see 2 fans on the rear, are these spinning and creating the noise you hear? My thought is perhaps just the onboard video has failed. Can you take a photo of the inside and post here?

Are there (hopefully) 2 LED lights on the case front? If so is one on constant (the power LED) and the other blinking erratically (Indicating the hard drive is spinning up)?

Your Windows 7 operating system is junk if the motherboard is dead, you cannot use it on any other motherboard. So the question becomes, is it worth salvaging parts to build another? And if you do not do the build yourself it will not be worth the effort

I'd take it to a Lenovo-authorized repair provider, let them diagnose the problem and suggest alternatives. Speculation from afar from a user community is nothing more than that, speculation. Let a trained person take a hands-on look to figure out what's needed.

It seems to be a low-end model, you may have a repair vs replace decision to make.

Not sure I agree Snidely, the OP has already been told a motherboard is not available probably due to the proprietary size of the case.

So after the fee to diagnose the issues we have $50+ for a cheaper motherboard, $50+ for a case, $80+ for an operating system assuming nothing else inside is proprietary so can be transferred. Then $100+ for a tech to build the new machine and offer 30 days warranty. Money would be better spent on a new confuser with a year warranty IMHO. New computers are very reasonably priced these days and often with more advanced gizmos included.

Turning it opening it up and systematically unplugging and replugging everything is worth doing: it's the first step in troubleshooting. Cables can come loose. Trace the connection from the video plug back to the motherboard (they come with built-in video, usually) and re-make the connection.

If the video chip has failed, it's basically unfixable.

Replacing the boards inside a case is not difficult ... as long as you can find a motherboard that fits. I'm not familiar with that model Lenovo, or what the needed motherboard size is.

However, it may be more geeky than you want to get.

You need to find a motherboard that will fit the case (If you have a Frys' electronics, they will look at it and let you know). BUT you also have the problem of finding a mobo that your CPU will fit into (they change) and that will accept your RAM (it changes too). Or buy new ones.

Every computer I have built or rebuilt started with a compatible mobo/CPU/RAM combo and I just screwed it into the case, plugged the CPU and RAM in, replugged the drives and power and fans and whatever add-in cards I was re-using ... and it was done.

Some of the computers were like Johnny Cash's Cadillac ...
http://www.youtube.com/watch?v=O4pAwosnIQE

This is what I might consider doing if it were mine. Probably it won't apply to you but then again, it might.

After confirming that it was really the motherboard and not a cable, video card or power supply, I'd consider bidding on a used board, such as this one. I'd first make sure that is the proper board, not bid over $40, and realize it's a gamble.

As for licensing, I know absolutely nothing but it's my impression that as long as you're replacing a defective board with the exact same model, you can use the same license. I assume activation by phone with an explanation would be needed though.

Maybe I'm misreading? From Microsoft's Licensing FAQ:

Q. Can a PC with an OEM Windows operating system have its motherboard upgraded and keep the same license? What if it was replaced because it was defective?

A. Generally, an end user can upgrade or replace all of the hardware components on a computer --except the motherboard-- and still retain the license for the original Microsoft OEM operating system software. If the motherboard is upgraded or replaced for reasons other than a defect, then a new computer has been created. Microsoft OEM operating system software cannot be transferred to the new computer, and the license of new operating system software is required. If the motherboard is replaced because it is defective, you do not need to acquire a new operating system license for the PC as long as the replacement motherboard is the same make/model or the same manufacturer's replacement/equivalent, as defined by the manufacturer's warranty.

The reason for this licensing rule primarily relates to the Microsoft Software License Terms and the support of the software covered by those terms. The Microsoft Software License Terms are a set of usage rights granted to the end user by the PC manufacturer, and relate only to rights for that software as installed on that particular PC. The system builder is required to support the software on the original PC. Understanding that end users, over time, upgrade their PCs with different components, Microsoft needed to have one base component "left standing" that would still define the original PC. Since the motherboard contains the CPU and is the "heart and soul" of the PC, when the motherboard is replaced (for reasons other than defect) a new PC is essentially created. The original system builder did not manufacture this new PC, and therefore cannot be expected to support it.

But like I say, that's just what I'd consider doing if it were mine.

Here's the "geeky part" from that auction:

It's a "Socket FM1 DDR3-1600 mATX Desktop Motherboard"

Socket FM1 - (the kind of receptacle the CPU plugs into, which is specific to the make and model of the computer chip - Intel or AMD use different sockets)

DDR3-1600 - (the kind of RAM chips it uses, the number may vary)

mATX Desktop Motherboard - (the "form factor", which is the shape and size of the board and the position of the plugs where your monitor and others things plug into the back. These have to match the holes in the case, although you may have fewer places to plug things in.)

==========
If you can find a geeky friend or co-worker, they might like to do it for you.

It's fun.

=========

Gigabit and Asus both make good replacement motherboards.

=========
And, (this is for snidely) .... don't worry about moving the OS.

Threaten them. If Microsoft gives you a hassle, sigh deeply and say, "Well, if you won't let me re-install Windows because of a defective motherboard, I guess I'll have to install Linux because I can't afford a new copy of Windows. I've heard Linux is pretty easy to use."

They should immediately give you a license key.

============
Don't worry about your data. The hard drive can be removed, plugged into an external hard drive carrier, and the date transferred to any new hard drive.

owbist, I'm not sure you and I are thinking on the same wavelength on this one. OP didn't say what "tech support" he was dealing with. If it's a third party yay-who, revert to my suggestion. If it's Lenovo or a Lenovo-authorized repairer saying that the part isn't available, then I'd say the game is over. There would be no issue of size compatibility if an OEM board for the model could be obtained.

To do something else is in the realm of "build your own computer", something that most people have no interest in doing personally or paying someone else to do. And for good reason. As we both said, getting a new PC may be the way to go.

It's bad luck to be having trouble with such a new PC but it happens. We've had nothing but great experiences with Lenovo products, we have several currently in use in the family.

Thanks to each and every one of you for the replies. Since I had purchased an extended warranty on the PC, the company has decided to replace instead of repair the computer. Thanks again for all the help!

Oh, fantastic news. Never had much faith in extended warranties but this time it surely has paid off nicely for you.

Thanks for coming back to let us know.

Happy computing :~)