my hardware is very prone to playing up as is the Vista x64 I have on it, didn't strike me as a hardware related problem.
I wasn't thinking of a directly hardware related problem as much as a combination of hardware and the OS. For example I have a 32bit Vista machine with a 2.17GHz single core processor, 256Mb DDR2 videocard and 2.5GB of RAM.That is all well over spec for Vista but the thing struggles, particularly the processor.

Most of the major browsers have had significant updates recently, and those can produce strange results in individual cases. I have certainly had problems with FF, although it seems to be OK now.