So in this case I need to get a new PSU, or a new MoBo?
Getting a new Mobo to check for the problem is a tad
expensive....
There are a few guys here who may be willing to lend you a spare
AMD-compatible mobo for you to test with. *points finger at
Pillow*
Try cleaning the dust off the computer parts to reduce the
probability of overheating and tweaking the BIOS settings that are
related to the system's temperature threshold as suggested in the
linked topic. Changing the CPU worked for some of them as well.
If all these don't work for you, you may still have to fork out
money to replace some of the components insde your box. Mind
telling us the PSU that is currently in use? And how old are the
CPU, mobo and PSU?