Thanks for the info! I kind of had a feeling that it may be related to using XP. Seem like most people that are running windows 7 aren't having any issues. Maybe it has to do with how xp handles the USB controllers. I may see about upgrading it to 7 instead of fighting with xp. 

I have heard all the profitability/ROI stuff so please don't bother. Just looking for some help getting my miners set up.

I purchased 4 of the new ASICminer USB block erupters (v. 3.0). I can't seem to get more than two to work at a time no matter what I do.
My desktop MB has:
6x onboard USB 2.0 port
2x front panel USB 2.0 ports
2x add on card USB 2.0 ports

I also have a externally powered (2A) 7 port USB hub.

I have tried endless configurations of connecting the miners using just the usb hub, 2 onboard ports and 2 front panel ports ...etc And no matter what I can only get cgminer to recognize two miners at a time. Any ideas what could be causing this? I am running Windows XP with a asus m4a785-m motherboard.