You can move all you pictures and other data to the external hard drive that you are not likely to need often to create space. Any uninstalled programs can be moved there to store. On the existing drive you might try running Ccleaner to remove excess files and a host of other odds and ends left behind over time. The program is free and very safe when ran with the default settings. Defrag after helps too. Ideally you need 20 to 25% free space on your C drive for the computer to work smoothly.

If you buy a used computer its always best to do a clean install of the OS and then reload what programs you want to run... You can still run some of the programs from your old hard drive by opening the folder of the program and clicking to run its executable file (.exe). Some will work, some won't, but none will continue to have an icon on your desktop unless and until you create a shortcut for it. .. I work with computers ALL the time. When you install a program it puts files in unseen folders as well as its main folder within Programs. It also puts certain information into bios and its from there that the program told to load and be prepared to launch.

It sounds like you want to move the data more then just back it up. You should be able to accomplish that with an external drive. The question is, do you have enough music or other files to warrant purchasing a 750 GB drive over a 320GB A couple things to remember, the external drives are great for a temporary storage medium, but I would rather have them on a solid medium as a backup such as a dvd. They do go bad as often as, and sometimes more often then internal drives. I have been working on computers for a long time, and I never understood why someone would back up the whole computer versus just their data. Most of the programs do not have the ability to restore your computer from a backup. You should have the setup cds or dvd from your computer so you should be able to (if needed) reinstall the operating system from scratch should the drive go bad or you get a virus that kills it. There are programs out there that can backup the whole system, but why would you want to? Raid, This is where you have 2 or more hard drives running the same data/ os. If your computer came with the ability to do a raid setup it is usually just 2 or more hard drives with the same data on it. For a detailed description it would be best to do a google search for it. There are different levels of raid. In my experience, the lower levels of raid aren't of much use. I have seen cases where the main drive dies and the data is not readable. In the higher levels of raid, it is spread out or stripped over several different drives and protects you from data loss. Over all, I think for home use it is just best to use a good backup strategy for data (CD or DVD or Tape) of the actual data and should something bad happen, you can restore the data and load the OS from scratch. Here is a link that might be useful: Raid defined

Don't be paying others to do these tasks. They can be part of the learning curve moving from XP to Vista. This is not a race, you can move forward at your leisure. If you are a nervous type person always remember you can walk away for a few minutes or more at any time. Just be sure to click Cancel rather than OK at those points in the process. Cancel stops things, OK approves the last move. You will not find 'My Documents' as they are now just 'Documents'. Same with My Pictures etc. Other things seem to have been needlessly moved but a few days of playing around will soon acclimatise you to Vista. Decide if you need the installed anti virus, it probably has a free 90 day intro. Vista firewall is 2 way so you can stay with that. Microsoft also provide an anti malware program on Vista, I think it is called Windows Defender and it seems to do the job. Friends have had it on their new HP since May and have stayed clean so it must be a capable program. Remember at some point sooner than later that you need to burn a set of recovery disks. My friend's HP required 3 DVDs to accomplish the task and you can only do this once. (I wonder why the restriction?) Enjoy your new machine. You will have to work very hard to fill that humongous hard drive.