Erratic behavior can be easily caused by a bad PSU. Do you have another PSU that you can try?
I assume there was some reason that you replaced, I assume replaced, your MOBO "Today I bought Gigabyte G41M-ES2L" -- what 'was' the problem?
The problem was I fucked up my old mobo by changing a setting in the bios which caused it to become unbootable.
I've fixed the current problem by the looks of things now thanks to your previous advice, the graphics card and WiFi PCI-E card were not seated correctly
Thanks very much for the help