Windows XP crashes – DRIVER_IRQL_NOT_LES

I work with Windows XP, IE6.0.
About 10 times a day, I get a blue screen (auto restart disabled…) that says something about
DRIVER_IRQL_NOT_LESS_OR_EQUAL
And gives the following info line:
STOP: 0x000000D1 (0x00000246, 0x00000002, 0x00000000, 0x00000246)

Now all parameters but the 1st and 4th are the same (which I understood that they mean IRQL 2 and trying to READ the memory). 1st parameter always equals the 4th parameter.

Can I understand from that what driver / hardware / software is making the trouble?

My only other option is to format my HD and re-install all, and well, I don’t really want to do that 🙂

Thanks!!!