Spyware, viruses, & security forum: Help with severe virus problem, please?

Ok, so here is my problem. I was on Myspace looking at a music artists' photos, when all of a sudden, my anti virus program (Avast Professional Edition, the one that you buy) pops up and tells me a whole bunch of viruses are invading my computer. After this occurrence, my internet has been really slow and unresponsive. Never again will I go on Myspace.

So over the past 5 days or so, I have been virus scanning my entire computer about 10 times, and my anti virus cannot find any more viruses. I have also done anti-spyware scans and I have eliminated a bunch of spyware, too. The problem hasn't gone away, though.

When I say my internet has been really messed up, I mean this: My anti virus' script blocker and all of the other blockers are on their highest settings along with Firefox's pop-up blocker, and I still get pop-ups, something I have almost never gotten before.

Besides this, when I try to visit websites, my Firefox error console gets riddled with error messages telling me it doesn't recognize or can't read a certain part of a website and it says "Declaration dropped." For example, on youtube, I looked on the error console and it said this: "Unknown Property 'zoom'. Declaration dropped."

Also, when I tried to install a registry clean up software, I got a message saying that the download wasn't a valid Win32 application or something of that sort. The download was from www.download.com, for the record. I eventually got one installed, but my internet hasn't shown any signs of improving.

By the way, when I typed in Firefox's website to try to re-install it, the website wouldn't load. It just wouldn't. Also, Google Chrome and Internet Explorer aren't any faster. In fact, most websites don't load for me at all. I can't check Email. On YouTube, the page itself will load, but when I click on a video, I get a black video window with a swirling load icon that would have stayed there for hours if I has just left it there.

What I also found quite intriguing was that whenever a pop-up appeared on my internet while using Firefox, it would say at the top of the window "Internet Explorer" despite me not being on Internet Explorer.

Also, I have tried to do a System Restore to multiple points within the past few months and every time my computer starts back up, I get a message telling me "Restoration Incomplete." The funny thing is that I am never told why.

My computer can still play video games and do almost everything else that doesn't include the internet just fine, but my internet is just so messed up.

I have the disc for the operating system I am running (Windows XP Professional), so I could re-install my operating system, but I really don't know a lot on this subject so I am waiting for advice on what to do.

One more thing: I have reset my router about 5 times and it has done nothing to help the problem.

Can someone please help me? My computer's internet has never acted this way.

Thank you!!!!!!!!