could be a graphics card problem.
I have had problems with the graphics config with it using generic drivers and I'm currently running a 1024x768 resolution on a 14" monitor which is less than comfortable! It seems to only like 1024x168 and 640x480 and when I try and force XF86Config to use 800x600 it seems to default to 640x480 and the taskbar doesn't fit on the screen! Although I can't be sure because I don't know where you can find out what resolution is currently running.
There's a listing of the graphics parts of my XF86Config files here http://www.knoppix.net/forum/viewtopic.php?t=2617 if you're interested.
But whenever I have had these "starting from cold the first time" problems it has usually been down to the Power Supply, normally however that manifests itself at the Power on Self Test stage in the bios and not after the OS has loaded.
odd
If you live anywhere near Bury St Edmunds you are welcome to pop over to my office and borrow bits to swap out to help you isolate the fault.
afraid not, but thanks for the offer.
Ben "tola" Francis