AVG for windows seems to get rid of the downloader, but sometimes it comes back. i personally don't thonk you can get rid of them uless you are willing to do a full system restore.
good luck!
http://www.ca.com/us/securityadvisor/virusinfo/virus.aspx?ID=62504
How do I get rid of this Virus?
purity scan ac - http://www.symantec.com/security_response/writeup.jsp?docid=2003-090516-2325-99&tabid=3
The spyware program 'PestPatrol' will remove it.
try free antivirus software AVG
Go here for a free virus scan and removal. Be patient, this is a very in depth scan and takes awhile. http://www.pandasoftware.com/activescan/com/default.asp?
virus virus
There are many sites that can guide you on this. One of my recommendations; http://wiki.castlecops.com/Malware_Removal_and_Prevention:_Introduction
IVE just updated my avg antivirus software and run it. It found downloader.briss and removed it to the virus vault.
Trojan downloader is I think spyware so get spyware doctor or a strong antivirus.
I shifted mine by pressing F5/F8 lots during bootup, going into safe mode with command prompt, and deleting them there. Ask an adult to help you ;)
I just ran a free scan with TREND MICRO Housecall 6.5 and got rid of it. In addition, it even fixes whatever mess this Trojan has left behind.