how do u - backup drivers using dos.....

For Microsoft Blue Screen, some of the error may rectified by restarting the sytem otherwise find the Error Code and let check in Microsoft and follow the steps as given. It may vary based on the error code.

how do u get error codes since that blue screen is like a flash it does not stay up to 3 seconds and it goes off.....

most error codes relate to memory management issues, and device drivers failing to register the devices in the middle of some operation. so if you can't make out which error code you are looking at, don't feel as if you have lost everything.
if i were you, i would only go ahead with a system reboot. if problem persists and halts all functioning of the computer, i would try updating all drivers, and make sure my ram is working properly, and there are no sync issues. if that doesn't help, i would do a full system's reinstallation.

From my point of view microsft blue screen of death has no solution than to let the system reboot or you doing it.
As most of you have mentioned, its to do with either a driver failure or hardware faults.
From experience, you can get this sort of problem when newer hardware has been installed but drivers not updated or not correct. i normally rectify this by booting in safe mode and uninstalling the drivers and find the correct.
Have you installed any hardware lately or memory upgrade? It could be that.
Also most companies like HP/Compaq, Sony and the others put drivers on their website.

If worse comes reinstall xp and sp1 and it'll install most drivers for you.

HTH

I agree with both of you. But I wanna share my experience here on blue scree problem.

Some of the problem may cause because of hardware failure as donanak said.

Bad sector formed in HDD so that OS was not loading and giving the Blue screen Error (for few seconds) I couldn't read the error message too.

I loaded the systemd with Recovery Console and ran the Chkdsk c:/f and scandsk. It marked the bad sector and rectified the issue.

In some of the case we need to reinstall the OS.

Under XP there is an option you can seelct to stop the system automatically rebooting itself after a serious error. Sometimes that can be useful as it gives you time to analyse the error message before it disappears. Do Properties on My Computer, Choose Advanced then click Settings under Startup and Recovery. There's a tick box there for Automatically Restart.
Not that this will help you with your current problem though...