My G/F laptop starts up to a black screen with the letter j followed by a blinking underscore, it was working ok ,she did a restart a couple of days ago and that's all it does now. operating system is windows xp. any advice would be appreciated
Cheers Lance

Not enough info. "did a restart" - what's that?

On booting, is there anything on the screen before the J/

Any disk light flashing to indicate disk activity?

closing down computer but clicked restart instead of shutdown, upon restart it goes to first page then goes to boot up page then goes black with the j_ the underscore keeps flashing
hope that helps a little
Thanks and cheers Lance

It's vague words like "first page" and "boot up page" that leave us not knowing exactly where you're at. And you didn't say what the disk was doing.

I'll assume that it's done the POST part of booting, which is what the Boot ROM does and it is now trying to bootstrap in the MBR (Master Boot Record) from disk.

If it hangs there (and there isn't enough evidence to be positive about this), then the MBR on disk could be damaged during your shutdown process. That glitch can happen for mul;tiple reasons - like knocking the computer during shut down; a power sppike at the wrong moment that could have happened earlier.

If this
diagnosis is correct, you would put the XP disk into your DVD drive, boot from that into the repair console and use FIXMBR to restore your MBR. Then the problem should go away.