My Book World Edition BIG TROUBLES

It’s six months now, since I had a virus and  fixed it with combofix, that I have big problems accessing the disk, the disk is a mirrored ethernet 2TB, my OS is Vista and almost every time I try to access the disk I have a total block of the PC (even the mouse stop) sometimes after a couple of minutes I regain the control of the machine but other times after 10 minutes I have to hard reset.

I already tried to change cables and access connection ( I have 3 hubs) but the situation is the same. I also have a Mac that have no such problems.

May somebody suggest something? Please help!

Trying to comprehend why a drive connected to the router will lock the PC

this is normal on USB drives but never heard of this on NAS

Also, the fact that the Mac does not have the issue shows that the drive might not be the problem