I've got an older Gateway E4100 with an Intel D865GLC mobo and I've just upgraded my video card from a GeForce 5200FX to a 7800GS. The new card requires a power supply of at least 400W and my current PSU is only 250W. I plan on upgrading it but I cant find any information on what type it is. I'm assuming it's an ATX, but it doesn't say anywhere on the unit or on any of the system spec programs I've ran. If anyone with more experience can guide me in the right direction, I'd appreciate it very much. Also, it's 6x5.5in, so is that just a standard PSU size? Thanks!