Driver problems

[Ghazban]

I've been getting a blue screen "DRIVER_IRQL_NOT_LESS_OR_EQUAL" error on my computer (running XP home edition) and I can't figure out exactly what's wrong. I searched around the 'net and got the impression that this means one or some of my drivers are out of date. Is there any free and easy way to check your whole system's drivers and update them all at once? I've found a couple pay sites that will do this but I'd rather not pay if there's a free way to do it. Thanks in advance.