Random crashing - related to tri video card?

[Piers Kittel <edinfo-list@biased.org>]

Added a new TNT2 Model 64 video card in my PC along with my AGP Geforce3 
and PCI TNT2 Model 64 making a total of 3 GFX cards.  Computer was 
running okay until around 10 mins ago, when it crashed.  Rebooted, LILO 
gave a strange error message.  Rebooted, the kernel stopped loading 
halfway.  Rebooted, LILO said CRC error.  Removed the new GFX card, and 
everything is okay again.

Is this some power supply issue, and if so, how do I make 100% sure 
without buying a new PSU?

Thanks very much for any help in advance

Cheers - Piers