I have exactly the same problem, only in my case the crash does not happen every time I boot the PC; it's happening when I try to access the C: drive. Strangely enough, the second HDD I have installed does not produce any problem (apart from becoming slow at times).
The message I get in the Event viewer is:
Faulting application explorer.exe, version 6.0.2800.1221, faulting module ~8076786880.tmp, version 0.0.0.0, fault address 0x00003a6a
I have checked HDD and memory, they work OK.
Mihakazi