And the computer in question is a Patriot CX300, with the part being a MXM145TF1. A minitower, set up so that the Power Supply cannot be more than 12cm deep - which is where the problem lies, since the standard ones are a couple of centimetres more.

Searches for Patriot doesn't help much.The company folded, and most of the stuff you get if you type Patriot in Google now tends to be sites featuring raving lunatics with a gun fetish. But that's potentially controversial thread drift (and I exaggerate a littel, not that much). Computers is what it's about here please.