PurityScan, created by Clickspring LLC, is a major threat to your computer's security. Also known as PuritySweep and Trojan.PurityScan, this Trojan downloads new software to your computer and creates pop-up advertisements that display on your screen. What makes this Trojan extra special is that it warns you of its mischief in its license agreement.

Unfortunately, removing Trojan.PurityScan is a long process if your anti-virus software doesn't remove it for you. It is important that you back up your files and registry before trying a Trojan.PurityScan removal technique, and you should only try it if you have experience with removing registry files.

Here's how to remove Trojan.PurityScan manually:

1. Press the CTRL + ALT + DEL keys to start your computer's Task Manager.
2. Click on the Processes tab.
3. Look for the word "PurityScan," right-click on it and choose End Process to make sure that the Trojan is disabled.
4. Search for Trojan.PurityScan by typing PurityScan into the search box in your Windows Start Menu.
5. Right click on the file and choose the Delete option.
6. Go to your Windows Start Menu again and click on the Accessories file, and then on the Run program.
7. Type “regedit” into the Run search box and press the OK button.
8. Choose the Edit option and then select the Find option.
9. Type "HKEY_CURRENT_USERsoftwaremicrosoftwindowscurrentversionruncontentservice" into the Find box.
10. Right click the file, choose the Modify option and then the Delete option.
11. Type "HKEY_CURRENT_USERsoftwaremicrosoftwindowscurrentversionruneudw" into the Find box.
12. Right click the file, choose the Modify option and then the Delete option.
13. Type "HKEY_CURRENT_USERsoftwaremicrosoftwindowscurrentversionrun ifu" into the Find box.
14. Right click the file, choose the Modify option and then the Delete option.
15. HKEY_CURRENT_USERsoftwarepuritysca" into the Find box.
16. Right click the file, choose the Modify option and then the Delete option.
17. Type "HKEY_CURRENT_USERsoftwarepuritysca" into the Find box.
18. Right click the file, choose the Modify option and then the Delete option.
19. Type "HKEY_LOCAL_MACHINEsoftwaremicrosoftwindowscurrentversionuninstallpurityscan" into the Find box.
20. Right click the file, choose the Modify option and then the Delete option.
21. Type "HKEY_CURRENT_USERsoftwaremicrosoftwindowscurrentversionrun aida" into the Find box.
22. Right click the file, choose the Modify option and then the Delete option.
23. Type "HKEY_CURRENT_USERsoftwaremicrosoftwindowscurrentversionrun brct" into the Find box.
24. Right click the file, choose the Modify option and then the Delete option.
25. Close the File Registry window.
26. Go to your Windows Start Menu again and click on the Accessories file and then on the Run program.
27. Type "cmd" into the Run search box and press the OK button.
28. In the command box type "cd," hit the spacebar and type the following:

• backup-20060321-124609-355.dll
• 41c6d56863.dll
• zvb.dll
• xulpcs.dll
• vzluoxiq.dll
• qyemk.dll
• rcagolbm.dll
• jdn.dll
• hakixk443.dl
• regsvr32 /u SampleDLLName.dll

29. Press the Enter key.

When the last step is done, close all open windows and restart your computer. The Trojan.PurityScan malware will be wiped from your system. Usually, Trojan.PurityScan is just part of a larger malware package, so you may want to run anti-virus scans for other malware that may be lurking on your computer.

At TopTenREVIEWS We Do the Research So You Don't Have To.™