Help me fix this to play on my PC

Hello,
I am having some problems with my computer.
This is hard to explain everything I have done over the last year of owning this in home PC. I received the Pc is perfect working order and like a idiot never installed a Anti-Virus. I surfed the web,my girlfriend surfed the web, my friends surfed the web. Alot of surfing. I play online games my girlfriend downloads games/music/everything. I finally started running into the problem that my computer had started to shut down. I knew I had virus's so I ran a cpl different virus protects multiple times. Spybot/AVG/I even have attempted registry fixes due to finding "wild Tangent" a very crappy virus/malware on my internet security registry keys. SO far in the past year I accumulated over 20,000 Malware Spyware and malicious critical threats and minimal threats. Basically if I had ever used my social security (wich I didn't) everything would have been stolen. I have narrowed it down to maybe 5 major virus's. One is called "Un-Wise" Wikipedia sent me to a sister website of computer wikipedia and the descrption of this virus is that it attachs to any MRU. Most recently used. It installed the wrong unistalled info on a random flashplayer type video game and is now havinng fun on my registry keys. Like my system start up and microsoft frontpage. One other virus is called "Quicken". This virus pretends to be the own your own bussiness program Quicken. You know to manage your payroll, monthly totals, yada yada this sort of thing. The awsome thing is that when I relised there was some weird program on my tool bar after work and clicked on it. It tells me that this file doesn't exist than crashes my system. CRASHES. Shuts down and takes me 5-10 times of restarting before my system gets past the window xp loading screen. on of the last major ones I will explain is "Wild Tangent".This is a very nasty little one. It completley hides now from all spybot avg reistry fixs anything i attempt to find it becomes a different virus. Haha sound weird? yah thats how I feel. I cant find it anywhere on my computer but now it sits on my reistry keys changing every second.
Reformat right? I've tried.. I have done everything to reformat correctly. Bought 4 windows xp/vista cd's now, changed my partions, changed to boot to disc. I am successful in the boot to disc but once I get to the little black screen a error screen comes up telling me that I have preform a ciritical error and windows shuts down immediatly.

Also, Everytime I go on the internet I run a spybot immediatly after. I always always always always have Tracking cookies.

Now to anyone who has sat through my mis-spellings and starnge way of explaining this and has any comments on immediate action to be taken please. Email me or respond. I just found this website by chanvce and am not sure of how to check for answers to me question. Thanks

P.S. I have ran all these in help mode no networking aswell