, burn the .iso to a blank cd. Restart the pc with the Memtest86+ cd in the drive, Memtest86+ should load up and perform a test of your memory. Test each stick of Memory one at a time and run each stick thru the complete test at least two times, unless you get errors. If either or both sticks generate any errors you should test them again but install them in different memory slots. Again, one stick at a time.
If either or both sticks generate errors in any slot you put them in then the memory is bad.
If the memory generates errors in one slot but not the other slot then the problem is probably with the memory slot that produced the errors.
Edit: Don't double or triple post, use the Edit button (looks like a pencil).