Rojash may well be correct, but as a further check you could try resetting the CMOS / BIOS configuration to default configuration settings.
Also, if that does not work, if the motherboard supports DUAL Channel memory, you could try testing with that function disabled from within the CMOS / BIOS configuration settings.
A third option is to run the MemTest86 memory checker on the system as OG suggests and see if that detects anything. Suggest you run it with a single memory module in each slot alternately, then with both in place. Let it run for some time.
Memtest86 iso (initially in .zip form), from which you can create/burn a Bootable startup disk, is available from:
http://www.memtest.org/download/4.20/memtest86+-4.20.iso.zip
As a matter of interest, what BSOD Error message number is displayed?