geforce 430 gt help

There are two possible causes, either the driver installation is just a bit wacky
or the power supply is failing to deliver enough juice to the card under load.

If it's the driver we'll want to completely scrub your nvidia control panel and graphics driver then reinstall fresh.
Do not use the nvidia uninstaller, it misses a ton of stuff.
Instead use this application to do the removal.
Phyxion.net - Driver Sweeper
For best results this should be done in safe mode.
Though you don't HAVE to be in safe mode to use it.
Also download the latest driver from nvidia before you start as once the drivers are removed everything on the screen will be enormous and it'll be hard to navigate until the new driver is installed again.
I suggest saving it to the desktop for ease of acces.
I can't link you to the latest available driver for that card without knowing whether you have 32bit or 64 bit windows.
You neglected to fill that out in your system information.

Are you using rivatuner, or any other application to adjust the timings or settings of the card?

Well based on what you've provided I can't really make anymore educated guesses.
A failing power supply is about the only other thing I can come up with based on what I've been told here.
If it was a bsod it would be much easier to troubleshoot in this manner, but there are just way too many possibilities to play the guessing game, we'd be going back and forth for days...

Yeah, speedfan is ancient I doubt it's causing the problem though unlike a lot of older stuff it seems to work just fine with win 7, we'd have seen a lot of instances of it, and I haven't seen anything in regards to speedfan causing problems with graphics.

Edit: it's kind of a long shot but since you can just let it run while you sleep I suppose you could do a full memory check outside of windows.
RAM - Test with Memtest86+
(it's best to let it run overnight to get a reliable result)
I do kind of doubt it's the ram, but it's also one of the only things we can really test right now.

You can also stress the card with this...
http://unigine.com/products/heaven/
and see if it also produces the problem.