I recently built a new computer for somebody. Everything seemed fine at first, but when I went to install the OS (tried both Windows XP and Windows 7), both installers would fail. XP failed with a BSOD, Windows 7 just said it could not read some file and the disk may be corrupt, although one time it BSOD'd as well.
I decided the next logical step would be to run Memtest86+ on it, so I booted into it and let it run for a while. I watched it for about 5 minutes with no errors reported, but I came back 45 minutes to an hour later and it was reporting over 15,000 errors. I opened it back up and removed/reseated the RAM. I even put them in the other set of DIMMs (dual channel with 4 DIMMs total).
When it came back up, Windows 7 installed and seemingly ran correctly. I thought "problem solved", but now, a day or so later, the system is back to BSODing. I have yet to run Memtest86+ on it again (haven't had time), but I suspect the same thing will happen.
Is it safe to say that the RAM I bought is faulty? Are there any other tests I should do to make sure that's the problem?