How to Clean My Computer if Windows XP is Infected

AVG Free Edition
1. Go to AVG.com and download free AVG.
2. When a pop-up screen appears asking you to Run or Save the program, select 'Save,' then choose the location on your computer where you want to save it. If the infected computer will not download or access the Internet, then download the program on another computer and save it to a memory stick. You do this by inserting the memory stick into the PC before downloading and when the pop-up window appears asking you to Save or Run, select 'Save' and choose the identified memory stick drive, which will probably be either E: or F: drive (depending on your PC).
3. Open the AVG program file from the location where you saved it and install it on the infected PC. If you had to save the program on a memory stick, then insert the memory stick into the USB port on the infected computer. When the memory-stick folder pop-up window opens, select 'Open Files' and locate the AVG program. Click twice and install the program on the infected PC. Follow the installation directions and click 'Finish.'
4. Wait for the AVG program screen to open. If the antivirus program does not open automatically go to 'Start,' 'All Programs,' and click on 'AVG' twice to open.
5. Select scan drives and click 'Start' so AVG will locate the infected files on Windows XP. When the program finishes the scan select 'Quarantine infected files.' If the program can't quarantine the infected files, select 'Delete infected files.'
6. Restart your computer and scan the drives with AVG again so the program can pick up and quarantine or delete any moving worms or Trojans.
Avira
7. Download the free version of Avira Antivir Personal.
8. When a pop-up screen appears asking you to Run or Save the program, select 'Save,' then choose the location on your computer where you want to save it. If the infected computer will not download or access the Internet, then download the program on another computer and save it to a memory stick. You do this by inserting the memory stick into the PC before downloading and when the pop-up window appears asking you to Save or Run, select 'Save' and choose the identified memory stick drive, which will probably be either E: or F: drive (depending on your PC).
9. Open the Avira program file from the location where you saved it and install it on the infected PC. If you had to save the program on a memory stick, then insert the memory stick into the USB port on the infected computer. When the memory-stick folder pop-up window opens, select 'Open Files' and locate the Avira program. Click twice and install the program on the infected PC. Follow the installation directions and click 'Finish.'
10. Select 'Scan System Now' when Avira program opens. If Avira does not open automatically go to 'Start,' 'All Programs,' and select 'Avira,' then choose 'Scan System Now.'
11. Restart your computer and scan the drives with Avira again so the program can pick up and quarantine or delete any moving worms or Trojans.
Avast
12. Download the free Avast version.
13. When a pop-up screen appears asking you to Run or Save the program, select 'Save,' then choose the location on your computer where you want to save it. If the infected computer will not download or access the Internet, then download the program on another computer and save it to a memory stick. You do this by inserting the memory stick into the PC before downloading and when the pop-up window appears asking you to Save or Run, select 'Save' and choose the identified memory stick drive, which will probably be either E: or F: drive (depending on your PC).
14. Open Avast from the location where you saved it by clicking twice. The installation will begin and follow the instructions and click 'Finish.'
15. The program should open automatically, but if it doesn't click 'Start,' 'All Programs,' then 'Avast.' Select 'Scan computer' and the antivirus will begin scanning Windows Xp in search of Virus infected files. When the scan is finished click 'Quarantine,' or 'Delete' infected files.
16. Restart the PC and scan the computer again with the Avast antivirus to make sure all infected files have been removed. If the program finds more infected files either delete or quarantine them and restart the computer.