I have a carputer system that has been up and running OK for about two years now, however recently it has failed to start and when i check the voltage across the positive and negative terminal of the computer it reads 4 or 6 volts, however if i remove the cables and test them off load then the voltage returns to 12v - 12.15...also if i remove the carputer and connect it to my power supply in the house it starts as normal.
I was wondering if any one has come across any thing like this with their own systems. ( a complete spec of my system is listed below.

I am thinking that it might be that the power supply is failing, however I have connected it in the house and it seems to work fine the rem line still turns on a little test car amp as well

System spec
E45M1-I DELUXE AMD Dual-Core APU motherboard with AMDŽ Radeon HD6320 and DirectX 11 Support
Corsair XMS3 2 x 4GB DDR3 Memory
OCZ 60 SSD (I also have a secondary drive for file storage that I took from a laptop 250GB western digital I think).
Powered by M2-ATX 6-24V DC/DC (160 Watts)
The Op for this beast is Windows 7 Ultimate 64 bit
Front end software is Centrafuse

this is how its all wired up the remote wire from the carputer (M2-ATX) is fed to the rem (remote) input of a rodek power cap, the cap rem output then feeds two amps, a bass maximizer, crossover and a load (approx 7) of old computer fans.

Thank in advance