I recommend 2 things.
A. Take ti back for warranty work, let them figure it out, it's what you have the warranty for. (i wouldn't, but I'm a tech.)
B. Run the Diags discussed above. If RAM or Hard Driver are bad, it doesn't matter what else you try to do, checking all the dumps in the world ain't going to fix it.
I generally say, let the Memtest run 4 to 6 hours with 4G. I would say for you to let it run 6 hours minimum to 8 to 9 hours max. It does generally (not always) work out to about 1 hour per gig these days.
The reason is the way the Memtests work. I don't fully understand it myself, but just know, it's not testing every bit of ram in a single pass. If you get errors right away, you can be pretty sure you have bad ram. But, there are false positives and false negatives.
So, I generally run both Memtest86+ and Windows Memory Diags to double check against each other. I have found that Windows Memory Diags give far less false positives/negatives than Memtest86+ does.
Which leads me to "
- Windows Memory Diagnostic NO LONGER RECOMMENDED"
I would like to see an explanation why.. as I think this is unfounded.