Thanks for all your suggestions.

I have had the RAM running in the PC for about 6 months and it is the recommended RAM for the Motherboard.

The trouble I am having is that the PC hangs on the POST screen, therefore I never actually get to the point where the floppy drive is accessed and thus can't load any diagnostic progrmas

I still reckon it is RAM related though as the RAM clock speed is 266 and the last bit of text on the screen before hanging says "Memory Clock is: DDR 200"

I've ordered some more RAM to seem if that is the problem.