Try replacing hard drive with known good hard drive and see if that solves the problem ... (I keep spare hard drives lying about that I've outgrown ... I keep them empty unless I'm actually using them, so when I put them into the non-working system, I have nothing on the drive to cause any kind of problems) ...

I also have bootable CDs that run Windows XP, Windows 7, and Linux Redhat ... plus a thumb drive (8 GB) with a good utility suite for fixing problems. You may want to think about doing something similar if you want to keep helping out your friends and family.

Programs I regularly keep and use:

Avira Anti-Virus - antivirus
Malwarebytes Anti-Malware - anti-malware
Spybot Search and Destroy - anti-spyware
Ad-Aware - anti-adware
CCleaner - registry cleaner, uninstaller
Defraggler - defragmenter
CCCP (Combined Community Codec Pack) - codec and media player
various video files in multiple formats to confirm that the system is capable of playing video and sound files properly...

It all fits on a single 700MB CD-R ... I generally charge 1 dollar for a disc, or give one free to anybody I helped out. I charge them 20 dollars per hour + parts or 20 dollars flat fee + cost of parts for family and friends/co-workers.

Now,, most should go to the repair environment .... if not , Now you need a repair disc to boot from if sounds like. A windows install disc is excellent to run repair from. What version windows you trying to get at ?

Holding power button in 5 seconds is a hardware reset most forget about - Which surprisingly, many have thanked ffor saving their beloved computer after much panic.

Mike,
For such things I boot a live linux Mint cd, If you have network capability you can download gnome disk utilities that will check SMART status and perform some further tests. Of course there are other linux choices.
I had one drive that could not be accessed by Mint, but Rescatux could and I was able to retrieve the drive contents with it.

Not enough info. to go on here, but with W7 or W8 you are instructed to burn your recovery disks and repair disk in the first week if possible of booting up your new PC. Because the OS disk no longer comes with a new PC. There are things that can be done however not knowing the exact problem, it's impossible to advise.

Only thing I think S.M.A.R.T is useful for is telling you how many times the hard drive has been spun up or started. 54,000 times or ? :) At least then you know its not brand new but you still don't know how old it is.

If you have the basics on a bootable USB stick and on a CD or DVD you are usually OK.

A bootable Linux stick or CD/DVD can be used to poke at a hard drive to see if it's still there.

WHDD at http://whdd.org/ is a well-recommended drive diagnostic and data rescue program..

http://www.howtogeek.com/howto/37659/the-beginners-guide-to-linux-disk-utilities/ has a whole bunch of stuff.

Also, having a decent-sized USB hard drive for rescuing data is good. Go in, grab the data and then you can do all kinds of things.