How do I permanently remove a trojan horse from my computer?

I have Avast! antivirus and it says that I have a trojan horse. So I quarantined it since that was the recomended action. The file name of the virus is nwinnldt.exe and the description is win32:downloader-ib[trj]. The antivirus quarantined kerell.dll, winsock.dll, and wsock32.dll along with it. Everytime I restart my computer the antivirus tells me that the same trojan horse is back in the same location. How do I remove it?

How do I permanently remove a trojan horse from my computer?nortan antivirus

Chances are it's hiding in your System Restore files and is simply recreating itself every time you reboot--which means that the recreation "stub" is still present as well.

First, you will need to get some software programs to help you. They are free for personal use.

Anti-Spyware Software

鈥?CWShredder - You can find it at [www.trendmicro.com/cwshredder]

鈥?Lavasoft's Ad-Aware - You can find it at [www.lavasoftusa.com]

鈥?Spybot S%26D - You can find it at [www.spybot.info]

鈥?AVG AntiSpyware - You can find it at [free.grisoft.com] / [www.ewido.net]

Anti-Virus Software

Download each of the above programs and then install them. After you install them, you MUST update them so you will have the latest protection. There is one small exception: CWShredder is a stand-alone program that doesn't need to be installed, but you do need to have it check for an update to ensure that you have the latest version. If you don't update these programs and you are infected with the latest parasites, you will not be able to effectively detect and clean them from your computer, so remember to update, update, update.