Did you put the USB stuff back into the same ports, or different ones?

Try one at a time and see which peripheral is causing the issue. 400W should be enough, but you could have a bad supply.

So... here are your test/result possibilities:

1. Same peripheral causes problem, regardless of other peripherals, happens in different USB ports: problem with peripheral.
2. Same combination of peripherals cause problem, regardless of ports used: probably power supply.
3. Port matters: bad usb port - don't use that one.


One other question - do any of the USB peripheral's have a drive, or anything that might look like one to the bios? You could be attempting to boot off of one of the USB devices. Try making sure the bios is set to boot off of the hard drive only.