how can I remove xena trojan with avast free

i have already cleaned my temporary internet files. Then I ran avast again and received the same results: a threat located in c;Documents and settings\new user\local settings\temporary inter…\xena[1].htm the status read Threat:JS:Prontexi-CX[Trj]

If anyone has suggestions on how to remove this as I have already placed it in the virus chest.Thank You.

Ads poisoning – JS:Prontexi
http://blog.avast.com/2010/02/18/ads-poisoning-–-jsprontexi/

i have already cleaned my temporary internet files.
did you use TFC cleaner ? if not try it

TFC - Temp File Cleaner by OldTimer
http://www.geekstogo.com/forum/files/file/187-tfc-temp-file-cleaner-by-oldtimer/
TFC requires a reboot immediately after running. Be sure to save any unsaved work before running TFC.

also try avast! boot scan
http://sites.google.com/site/spg20scottsweb/home/avast-5-boot-time-scan