Memory problems.

Technical Level : Basic

Summary

Memtest is easy to use and is an accurate test of your computer memory.

It can tell you if your memory is bad, a motherboard slot is bad etc.

Please note it takes a fair amount of time to run the required 6-8 passes.

Overnight is often best.

Memtest is better than the built in memory tester because it tests outside the Windows environment thus eliminating everything else.

Details

1. Download Memtest here and follow the instructions to burn it to a CD. It will also work if burned to a bootable USB drive.
2. Burn the downloaded image to a CD or bootable USB drive
3. Boot from the Memtest media and start running it.
4. Yours should look like this. (no errors)

5. Let the first pass run and observe the report after the first pass.
There should no errors.
If there are it will look like this

6. If no errors, continue running the other 7 passes.
7. If at the end of 8 passes there are no errors you can be fairly sure your memory is working correctly.

Any time Memtest reports errors, it can be either bad RAM or a bad motherboard slot.
Test the sticks individually, and if you find a good one, test it in all slots.

Any errors are indicative of a memory problem.
If a known good stick fails in a motherboard slot it is probably the slot.
If you do have errors be sure to revert back to the default timing for your ram.

You can confirm this by moving that stick to another slot. If the result is the same it is the memory, if it is different it is the slot.

Don't overclock, or undervolt it until the errors have stopped.
Similarly, if you are overclocking in general, revert back to default for the duration of these tests