Still finding malware on my computer even after scanned and remove malware

i have two legitimate anti-virus programs, SuperAntiSpyware and Malwarebyte, yet they still managed to find some kind of malware or adware on my computer. Due to my lack of keen judgement, I bought the AV security basic suite virus software because I thought there were trojans on my computer When they suggested I buy there anti-virus software, not knowing that it was an infamous anti0virus scam trojan. The first time I used SuperAntiSpyware and Malwarebyte AV software to remove the trojan horses that AV security basic produced , it removed tons of threats, which were around 800-2000 threats. I now continually perform scans for malware and adware, and both AV programs seemed to find new threats , but the threats are not as numerous as they were when I performed the initial scans. The number of threats range from 2-7. based on this pattern , I don't think that I successfully completely removed all of the malware and/or adware produced by the AV security basic trojan horse because I continued to find new malware and adware on my computer everytime I perform an anti-virus scan. I think the trojan horse went into remission and was programmed to make the user think that they have removed a large all of the malware/adware when the initial scan was first carried out . How would I resolved this issue? The anti-virus programs that I downloaded don't seem to be working very adequately .

PS. I can't access firefox web browser anymore. Everytime that I attempt to , the message that appears is ""The application or DLL C:\Program Files\Mozilla Firefox\xul.dll is not a valid Windows image. Please check this against your installation diskette." When I attempt to upgrade firefox, it says that the new firefox program is not compitable with my operating system, which is ridiculous because I have windows XP as an operating system. Is being unable to not access fire fox have anything to do with my AV security software trojan horse? What should I do in order to access and operate the firefox web browser again?

Download OTL by OldTimer to your Desktop.

• Close all windows and double click OTL.exe
  
• Click Run Scan and let the program run uninterrupted
  
• It will produce two logs for you, one will pop up - OTL.txt, the other will be saved on your Desktop - Extras.txt. Post both logs in this thread.
  
• You may need to use two posts to get it all.