In my many years of working in IT, this is the first time I've come across a file which I couldn't delete... eventually.
Either this is a first, or I'm going senile...
A customer's Win2K/NTFS machine was infected with spyware and Trojans and I eventually managed to get rid of pretty much everything apart from some spyware thing called TV Media and a dll file in System32 called MSLG.DLL - a trojan which AVG pointed out but couldn't do anything with.
The entries which start it up in the registry are immediately replaced when you try to remove them - even in safe mode.
Same thing with HijackThis - rescan after removing three entries and they are back again - even in Safe Mode!
Boot into command prompt mode and it still won't delete - it shows up as a Read Only, BUT you get an Access Denied error when you try to remove the Read Only status with attrib.
So I brought the drive home and put it into my clean XP machine (using USB2 external case so I didn't have to boot with it attached) and once again, AVG detects the dll but still won't remove it.
And, although it's no longer in memory, I still can't change the attributes or delete the damn file - I just get Access Denied.
This one has me stumped!