IRQL not less or equal error help needed

I have a custom built system. Antec true power 380 watts, 1 GIG ram, 9600 series radeon video card, intel P-4 3.0 gig HT processor, abit vt7 system board, on board lan, audio, maxtor 40 gig HD. CD-ROM-RW combo drive. All was fine until a week ago. Started getting IRQL not less or equal BSOD error when playing a game magic vines. All was OK until now, was playing internet radio, tried to go to a website, got error again. thanks in advance for any help.