Where to start...

*Please read, I know it's long * OK, so I had a big problem with viruses and spyware that I could not get rid of, no matter how many different things I did/tried. So, I decided to reformat (in which my friend guided me through), but all we did was reinstall Windows on top of the old one or something? I don't know exactly what we did, but none of my files were gone, and I still had tons and tons of yuckware problems, this time including porno ads on startup. So, I decided to take it to a different friend's dad, in which he did a "clean install," I guess, of my Windows XP and deleted the partitions that the old drives left/made? So I get done with that, go try to download SP1 (which has never worked for me on the first-third tries because it freezes). I keep trying, while in the meantime downloading mIRC to talk to my Counter-Strike team and let them know I'm alive after some odd weeks. So SP1 finally finishes, I keep downloading all the other critical updates over hours' time, and get finished with that. I then installed Norton Anti-Virus, which later showed me having 25 viruses or something that I eventually got rid of in safe mode. After, I downloaded Ventrilo (to again, talk to my CS team). Seeing that I got a 3000 ping in Ventrilo when I normally get 50-90, I figured something was wrong with my internet connection. I downloaded Adaware, and it deleted 385 or so bugs. No more virus errors have come up, but every time I run it I get 25 bugs. I've noticed 2-10 web search toolbars or some crap keep getting installed on my computer unknowningly, and I still can't get my internet connection to be like it was before I tried the reformatting. After about 30 minutes of web surfing, I get continuous DNS errors and I can't connect to anything internet related. Wow, for some reason (and I can't figure out), I'm getting really P/O'ed... Thanks for the time reading this, and any help granted toward me...

*EDIT* By the way, I use Verizon DSL, which I don't think is having problems, but who knows. Also, another person I've talked to has the same problem with me (spikes in internet after reformatting) but he uses a different ISP.