[JGZinv]

@ the op - besides running a drive diagnostic from the manufacturer, I'd suggest looking at a non destructive
reinstall of the Windows system files. Drive diagnostic should be from the mfg's site under support somewhere.

http://www.informationweek.com/news/windows/showArticle.jhtml?articleID=189400897&pgno=1&queryText=&isPrev=

Then yeah, run that thing through viral tests. Malwarebytes Anti-malware, Eset online scanner, Avira, Spybot S&D, Adaware, CCleaner
will be a good start.

All of that is free.

[jr2]

I'd suggest having the latest Hiren's Boot CD and Falcon Four's UBCD available in burnt format at all times.  And (personally) the latest Linux Mint Live DVD.  All of your troubleshooting needs in three disks.  F4's is a modded Hiren's, but he includes some rather nice add-ons (SpinRite, for example, is your best shot at recovering from a damaged hard disk without sending it to data recovery -- although if it won't turn on, you may need to cover the hard disk with a towel and cover that with an ice-pack).  Most usually Hiren's and F4's can be found from torrent sites... sort by # of seeders and download with uTorrent.  (Turn on outgoing protocol encryption and disable "enable incoming legacy connections").  Also, PeerBlock is your friend. 

[S-99]

Get yourself the gparted livecd which is not hard drive brand specific and works on all computers (most hard drive utilities from a manufacturer are unfortunately brand specific).

You can pull a memory scan and test with it to check your memory first (in case it is the memory). Then you can check out the hard drive with the livecd too.

If the hard drive is junk, chuck it. If the memory is junk, chuck it. I hate it when people give sort of working computer hardware to other people. Sounds like the hard drive is the problem to me and other people as well.

@ Jr2
I don't recommend getting too fancy with livecd's (a lot of livecd's for different purposes gets complicated and can make getting things done slower). I usually just use gparted and my linux mint custom respin. I recommend using remastersys to make your own custom linux mint livecd. Linux mint does come with a lot of software, but i found it lacking (one biggie it misses is a formatting utility...now it includes gparted, guess i'm down to one livecd). If i need a livecd with more capabilities, i'll tweak my current install and get the appropriate programs and respin a custom livecd with remastersys. One livecd for all things is what i have made and recommend.

[SpardaSon21]

For anyone wondering, I installed a new HDD and a new installation of Windows, and no issues so far.  The previous HDD crapped out during the installation of IE8 (not that I use it, but Windows loves IE) and was slow as hell before it died, and this one is great with no speed issues and everything installed fine so far.  I just wish it wasn't 250 gigs smaller, but I didn't have to buy this so no complaints.