|"Do you think that it could be a fault with the 220v mains wiring loom in the house?"|
Is it aluminum wiring, or copper?
The connection of the computer to the AC in the wall, and the connection of the wall socket MUST be grounded and wired properly.
There may be an led or leds on the belkin surge protector that indicates whether it is detecting a wiring fault and/or that that it's grounded properly.
A surge protector often will not be enough to protect against damage caused by a nearby ligtning strike or a lightning strike on the power grid near you. The only sure protection from that is to unplug everything that plugs into AC that plugs into your computer, AND the cable that connects you to the internet when there is lightning in your area - your computer doesn't have to be running, and whatever you have it plugged into can be switched off , yet the voltage spike or surge caused by the lightning can still get through because it's beyond what the surge protection device can handle, or if the voltage spike is a high enough voltage it can jump across switched off circuit connections.
Is it possible there was a lightning storm before the power supplies failed?
Don't buy an el-cheapo PS.
See response 3 in this:
I checked your mboard model and cpu. The Rev. 1.x mboard will handle up to 125 watt Phenoms, the Rev 2.x mboard up to 140 watt Phenoms, the cpu draws 95 watts, so the mboard can definately handle that (some older mboard models can't handle more than an 85watt Phenom).