I get a strange sort of screeching noise like high pitch bleeping but very faint as well as the power cuts on and of ever miller second almost like when a car wont start it when it tries to turn over i have tried all sorts iv removed everything from the motherboard so its just the motherboard and the psu and also tried about 17 different psu's so its not that...its a issue with the motherboard i know but what? or is it F****D?
It's probably the motherboard then I guess (without just replacing it ) is to rule out the PSU and hard drive(s), assuming you've got other one's you can try in it. Also there was problems with certain periphial devices namely the mouse. I remember a while back that a friend of mine had the same issue and it turned out that it stoped when he would move the mouse after the computer sat for a minute without use. Also the old 8800 GPUs would cause this issue. The last thing I can think of would be a CAP on the board somewhere about to end its life. Either way the steps I would take would first be to unplug the drive(s) and see if noise stops, next try the GPU. Ruling out parts one at a time to come to the conclusion that it really is the board.....Good Luck