Help with lag probs!! PLEASE!!!

Ok, I'm at a point that I'm about to throw my husbands computer out the window. I cannot for some reason get SL to run smoothly on his computer. I had my own computer that had a lot slower processor, ram and video card wise, but SL ran beautifully. We went and bought him his own computer earlier this year and SL runs like *$^#.

I have lowered every detail i possibly could in the preferences and still no luck.

He has the GeForce FX 5500 graphics card, over 1k of memory, a AMD Semphron 3400+ Processor, and we run on dsl for internet.

I've tried updating the drivers, but if someone could pinpoint which exact driver to use for this video card, that would be helpful then just directing you to the nVidia webpage. I've also read about the drivers for the motherboard chipset but that scares me to no end on messing with that (thats all i need to do is download a driver for the motherboard and crash his computer lol)

Any help would be greatly appreciated. I'm an online DJ and its frustrating to be DJ'ing and doing an event to just watch your av move as slow as molasses in January while dancing...or typing...or just plain doing anything!!

i have same issue with nvidia 5500 but i only have the 512mb ram.
i have left a forum message to be answered with nvidia, idk if same with you, but my secondlife preferences only go to 128mb as highest video card, as the 5500 is 256mb. so i am crashing as soon as i log on. mine is pci, although i have seen them as agp.
the sticker on your computer when you bought it should tell you whether it is an agp or pci. there is a agp accelerator in graphics preferences for SL you can check mark for better performance.

make sure he has directx 9 and updated. type in RUN>dxdiag
This will give you a test of directx 9. if you are unable to do the tests on the dispay pages, then you need to update it. search for directx 9 on web adn download. usually in microsoft website.

gl to you