If it's not the modular Hiper (HPU-4M580) I'm going to contradict mpilch here and say the Hiper is more than adequate. A single 8800GTS doesn't use that much power and the CPU has it's own rail (+12V2) so there's plenty of power for even a quad core.
If it's the modular Type-R, I would definitely NOT use that PSU for either a Socket 775 board or SLI or a single graphics card requiring more than one PCI-e connector.
If it is the TYpe-R, there's a couple reasons why you shouldn't use it for the build you list:
1. No native 8-pin EPS12V connector. The 580W only provides the 4-pin. You can use just the four, but I've seen pins on the board burn when trying to power high power Intel CPU's with only two hot wires and two grounds. You could use a 4 to 8-pin adapter, but as it is the two +12V leads on the 4-pin are split off of a single wire and the two grounds are split off of a single wire creating a lot of resistance, so adding an adapter to that is only going to make things worse. Pins on the board might not burn up, but connector on the PSU will, if the PC even has a chance to run that long.
2. There's only one native PCI-e connector. The 8800GTS needs two. Sure, there's a Molex to PCI-e adapter, but that's not necessarily a good solution for the same reasons using a 4-pin to 8-pin adapter for CPU power isn't a good solution.
If it's the one in your sig and that part number is correct, you have a black Type-R. If so, ditch it. Sell it with your old parts... it's a good PSU, but it's antiquated by today's standards and completely unsuitable for a modern, high-end machine.