Last night my machine started to play up by not completing the boot up process. Each time I started up, the process would get get less far into the boot - now it does nothing at all. I have tried booting up with operating system [XP Pro] - nothing. Machine is powered up OK - as is the monitor - just a blank screen, not even getting to memeory check. What's going on? I have been using the system [self-built] for at least 2 years with no problems.