Please Help us to Help you In order to help fully we need more information....
- What Operating System are you using ? is it up to date ?
- What avast! version and VPS file (virus database) number, e.g. 0630-2 (see about avast!) ?
- What was the file name, where was it found example (C:\windows\system32\infected-file-name.xxx) ?
Or was the location a URL, in any case this information should be in the Warning section of the avast Log Viewer.
- What actions have you taken to try and resolve the problem ?