MBR repeatedly corrupted?

kenaniah7037

Honorable
Sep 17, 2013
54
0
10,660
Allrighty, here's what I've got:

Been working on a client's Dell XPS Studio notebook. Replaced HD (old one was definitely failing, access speeds were ridiculous), re-installed fresh copy of 7. All drivers and firmware updated.
New problem: Often when he shuts it down, the MBR corrupts. Boot failure.
Using the install disk repair option works, seems to repair the MBR. Everything runs fine for a few restarts, then it does it again.
The HD is less than 6 months old. The RAM was upgraded about a year ago. So I'm not convinced yet that it's a hardware issue. but I'm open to being wrong on that call.
This problem started immediately after he clicked on a file in an email and downloaded a really special virus, which took me some time to remove. I can't find any traces of the virus left after many different scans at different levels, but now I'm beginning to wonder.
It even seemed to wipe his files on a USB stick that was attached at the time, although I was able to recover them in Windows 8. Afterwards, I wiped and reformatted the stick, so it should be clean.

Ideas, anyone? Thanks for the help!