sweenmachine,
You have got to be more specific about your Dell. I have in my household 4 that are on essentially 18/7, and in my practice several hundred. I have never had to adjust the hardware slider except in one case of a specific game.
Several points to consider:
1. Dell in the main uses ATI and not nvidia for its laptops chips. If you managed to install nvidia drivers I suspect you made a mistake.
2. The top two p.i.a. of computers have to be video and sound drivers. I am not saying they are easy to make work correctly. But keeping current, letting XP do its thing in terms of IRQs, etc. is usually better than trying to outguess the OS and do it yourself. Particularly for a laptop, I really recommend you do not try and fiddle with what is discovered by the OS as a working arrangement. It reminds me of when my neighbor bought a Porsche Boxster with the automatic transmission option. Another neighbor was very critical about the issue. I told him that he was absolutely right, except that in urban driving situations like ours the auto will shift faster and better than you could by hand, and if necessary you could always turn it off and manually fiddle.