Recently I've tried to boot using rescue floppies and after POST the screen would flicker. I opened the case to check for loose connections. I found no loose connections but a whole lot of dust & lint on the CPU heat sink.
I removed and cleaned the heat sink and fan. Also one of my CD ROM drives had died a while back so I took the opportunity to remove it.
When I switched the P.C back on it would come to life and after about 10 seconds shut down again. Any ideas how to fix this?