You can download your motherboard manual from here:
M2N32-SLI Deluxe User's Manual for English Edtion(E2697)
This manual shows the two yellow RAM slots closest to the CPU, the two black slots on the outside.
If this is the same as your motherboard, this manual you need to use.
If you have a manual that shows yellow-black-yellow-black RAM slots and your motherboard isn't configured that way, it is the wrong manual.
You can install your RAM cards in the two yellow RAM slots, they should be together and closest to the CPU.
When running
memtest86+ you can put a single RAM card in any slot for the test. It is best to test with the slots that you are using now.
I recommend running memtest86+ with both RAM cards installed, in slots A1 and B1.
It is best to run the test for a full 7 passes, overnight is the easiest.
If you get any errors you can stop the test.
If the tests has no errors or does not stop by itself, that means it has passed this test.
If you get any errors in the first test, then follow the instructions below.
For the single RAM card test:
Take the RAM card out of slot B1, test the RAM card that is in slot A1.
It is best to run the test for a full 7 passes, overnight is the easiest.
If you get any errors you can stop the test.
Pass or fail, take the RAM card out of slot A1 and put the other RAM card into slot B1 and run memtest86+ again, same as above.
Have you checked you CPU core temperatures recently?
Are you installing Windows 7 32 bit or Windows 7 64bit?