So, I found my old IBM desktop in my storage and decided disassemble it and use it for retro gaming. The problem? It's not powering up. Whenever I connect it to wall socket, the PSU just creates a soft 'thump' sound and the power light just turns on. Nothing else. No fans spinning, no noise, nothing. Anyone know what to do. I think the PSU's messed up. The computer's a Pentium 4@2.60GHz, 4x 256 MB DDR RAM and 40 GB of Ultra ATA HDD. Note, this computer was last used in 2014 and the last thing I remember about it is that it had a boot sequence error after which it never output display again and has been in my attic catching dust ever since