Is my power supply enough?

Hi all, was hoping somebody with more knowledge than me might be able to help me out. I've been dealing with some recent crashes and boot problems with my system and i'm trying to track down the cause.

Basically the problem is that I'm having trouble getting my system to boot -- sometimes it will hang while detecting USB devices, sometimes it won't detect my hard drives. Occasionally my system will boot and be OK for a while until I try to do something intensive like playing a game. Often I'll get into the game for a few minutes but then the system will simply restart.

I seems to have temporarily solved the problem by pulling out one of my video cards (I'm running 8800 GTS's in SLI.) At first I thought one of the cards had died but they both seem to work fine individually.

Could it be my power supply isn't beefy enough for my system? It seems possible since these problems started after adding a spot fan to my system to help cool the memory. Here's what i'm running:

Thermaltake Toughpower 700W PSU
MSI P6N SLI Platinum motherboard
Q6600 CPU w/ stock cooling
4 sticks (4gb) 800mhz ram running at 2v
8800 GTS 640mb x2 in SLI
3 SATA hard drives
2 IDE DVD drives
1 Audigy 2 sound card
2 120mm fans + 1 internal spot fan for the memory
Floppy drive
Couple other small items that might be drawing power like a northbridge fan and a small LCD panel on the case that displays internal temperatures.

I think that's about it. When I bought my power supply a while back I figured it was going to be able to take whatever I threw at it. Is there any way I could better divide the components to avoid the power problems?

I'm also open to other suggestions about what might be causing the problem.

Thanks again for your help!

No overclocking?

How old is the PSU, overtime there power rating will lower with aging components. Although the 700w should be plenty

Try resetting CMOS and following theAnimal to try to narrow down the issue.