Scans appear clean, internet buggy and slow

A few days ago my laptop started acting very sluggish while browsing the web. Scan with Spybot S&D revealed a few infections, most of them variations of Vundo and Virtumonde. I cleaned the infection, and rescanned with Spybot, Avast!, Symantec, VundoFix (Ad-Aware keeps saying 'could not connect to service', and Malwarebytes always freezes and can't be shut off). All subsequent scans have been clean. I bought a router to hide behind, uninstalled and reinstalled firefox, and tried virus scanning in safe mode (clean). I cleaned all my temporary internet files, cookies, cache, etc., but Firefox is still buggy. It often takes a long time to to load images and videos. When I log into Facebook and try to go to my profile, it simply says "done" and reloads the page I'm on.

I am running Windows XP Professional with service pack 3.

Any help would be hugely appreciated!

If you are not finding any more malware, then either there is more malicious files hidden (undetected) on your system causing problems or the issue is with Firefox.

Optimizing FireFox:

• Firefox Tweak Guide
• How To Make Firefox Faster
• Firefox Running Slow? Problematic Extensions Could Be The Reason!
• Basic Troubleshooting for Firefox
• Firefox Running Slow?

Note: Due to the way Firefox caches pages it will use more RAM the longer the browser is open. Closing and restarting more often will clear that out and should lower your resource usage dramatically.

I'm afraid the problem has worsened. I can now no longer access the internet. The task manager says there is no network detected, and the device manager shows all networking hardware in an error state, saying that the drivers are missing or corrupted.

Try performing an Online Virus Scan like BitDefender or Kaspersky to see if they detect any malware.

I cannot access the internet from the affected computer. Sadly, I'm going to have to have the school wipe the harddrive and reload windows and the other base programs. At least I backed up my files before it blew up =X Thank you for your time, though.