You might also find some good ideas for your problem at <A HREF="http://www.geforcefaq.com" target="_new">http://www.geforcefaq.com</A>.
Similar to the Geforce256 cards, the TNT2 cards were also fairly power hungry. Difficulty with these cards have been seen in many Super7 motherboards and earch Athlon/Duron motherboards. If a video card is causing stability problems (as opposed to drivers, etc) the 2nd best work-around is a power supply with ample current capability, especially on +5volt and +3.3volt lines. 20 amps on each should be considered a minumum for a Geforce256 on an Athlon/Duron system. (I would guess 16 to 20 amps should be considered the minumum for a TNT2). However, I don't consider having just the minimum very reassuring. Like most people, I recommend Enermax PSUs. I have the EG351P-VE, 330 watts, for my Duron system but I recommend the Enermax's newer model, the EG365P-VE, 350 watts, as my personal "minimum". One might need more if he/she has system with 8 drives, 12 fans, 2 NICs, etc. but for a modest system, even with a top CPU and video card the EG365P-VE should be enough.
Would you like a Quarter Pounder?
No, thank you. Just give me the BIG heatsink. It's an Athlon.