I will have a look at it tomorrow. Problem is that I don't use Vista myself i.e. I don't know if the computer will even run if winlogon.exe process is stopped.

Does the command prompt go away when you end the explorer process? If it doesn't then there should be no problem deleting it through there.

Anyways like I said I will have a closer look tomorrow.

Edit: I just tried ending the explorer.exe process in XP while keeping the command prompt and it worked. So try doing that in Vista

If it does then give me the complete path to the file you want to delete and I will give you step be step instructions