Hello apineda and welcome to BC
Sorry about the delayed response. We are all volunteers here and sometimes things slip past us. In order to provide you with the proper disinfection procedures, we need some additional information.
What is your Operating System: Windows XP, Vista, etc.?
What security programs do you have installed besides the Sophos AV you just installed?
How did you become aware of the file in question?
What is the file path? An example of a file path is: C:\WINDOWS\SYSTEM\VGA.DRV in which VGA.DRV is the file, SYSTEM is the folder it's in, WINDOWS is the folder SYSTEM is in and C is the drive WINDOWS is on.
Are you experiencing any issues with the computer?
Help us help you. If HelpBot replies, you MUST follow step 1 in its reply so we know you need help.
An ounce of prevention is worth a pound of cure
SpywareBlaster, WinPatrol Plus, ESET Internet Security, NoScript Firefox ext.