Sorry for the latish reply, haven't really had the time to look at my computer again and am not in a rush too since ive got my laptop but what happens you start the computer up, it turns on, then the power flicks back off again, then on, then the beeping starts as it boots up. As for the HSF, the Fan looks like it tries to spin but only kinda gets a flick and then tries again in another 5secs and again only gets a flick. After this the HSF doesn't try to start again.
Do you think I should try replacing the HSF first?
Although the HSF is only 6 months or so old, I do always leave my computer on and really has hardly ever been turned off, so it has been run quite a bit.