The temp seems to be within limits.
You must run memtest86+ it's the best ram test you'll ever find. Also if you have some fancy DDR3 memory kit, make sure you have them plug in the correct slots on the mobo (you should find some specs in the manual regarding the triple channel setup and all that).
Also when testing the ram, you must do several test. 1. Test the memory modules they way they are set up now. 2. In case you get errors and you have more than 1 module, test each module alone on all the slots.
If one module gives error on more than one slot it's the module. If both modules give errors on the same slot, that memory slot on the mobo might be the problem.
Also (with the risk of Gizmo editing my post but hopefully since I'm part of the somewhat active members here, he won't :D) why would you pay for Windows 7? Just download it.