Now I have done, and I think I have found out what circumstances produce the problem.

If I leave the 7-port hub unpowered (it has its own wall-wart) I can plug everything* in, flip the switch, and everything works. If I have the hub connected to its power supply when I flip the switch, the computer stays dead.

Is there a limit to how many USB items can be connected? What are the ramifications of running that hub without its external power source connected? It seems to be doing nicely without it, and everything works the same whether it's plugged in or not, except that my computer won't turn on from a cold start when the hub is plugged in.

I just finished sorting through and "neatifying" my cabling, and was appalled at everything I have connected.

*AC Connections:
1) Computer
2) Monitor
3) Printer
4) Scanner
5) USB External HD
6) Speakers
7) empeg
8) Karma
9) Wireless headphone transmitter
10) Charger for Panasonic camera battery
11) Charger for Olympus camera battery
12) Charger for cell phone
13) Charger for razor
14) Charger for bicycle light
16) Second surge-protected power strip
16) [Power supply for 7-port USB hub]

USB Connections
1) 7-port USB Hub
2) Mouse
3) Printer
4) Scanner
5) USB hard drive
6) empeg
7) Karma
8) Panasonic camera
9) Olympus camera
10) Card reader

Now I'm feeling unfulfilled... I still have three USB ports and four AC outlets with nothing in them.

tanstaafl.