Do you know the possible location and file name of the suspect virus, e.g. (C:\windows\system32\infected-file-name.xxx) ?
Send the sample to
virus@avast.com zipped and password protected with password in email body andundetected malware in the subject. Or you can also add the file to the User Files (File, Add) section of the avast chest and send it from there (right click, email to Alwil Software).
In the symantec page you found, there is likely to be technical information and removal information, etc. so you don't have to buy anything. It may appear that only symantec detects it but the malware could have aliases as there is no standard naming convention.
Files that keep coming back most likely have other elements to restore it.
If you haven't already got this software (freeware), download, install, update and run it, preferably in safe mode.
1.
Ewido, a.k.a. avg anti-spyware If using winXP. or
a-Squared free if using win98/ME.