Halo there… I have come across the same problem with VISTA Home Premium… The file your looking for would be sitting in this location: WINDOWS\pc-off.bat. However, I can aslo confirm that your P.C is infected. The solution I have found with this is to scan with NOD32 Anti-virus 4, even the trial can get rid of it for free….
It is also best to carry out scan with Malwarebytes and Trojan Remover programs. you’ll be surprise to what they can find comapre to your Anit-virus.
Hope this help.