im on windows 7 x64, i had hub issues, check under Devices and printers , make sure all your hubs are there, its possiblöe there is one that not installed driver correctly.
Also i noticed windows doesnt like it if you mix and match USB hubs, powered, vs non powered, and usb3 vs usb2. it get very temperment, espe cailly a powered usb3 hub, wiht a usb2 unpowered daisy chained off it. no go, sometimes maybe if it wants. My recommmendation is to try and stick to the same type of hub when daisy chain them together. right down to make and mode.
Yes I have 2 Powered USB 10 Port hubs, both the same... I unplugged the Unpowered ones, so far I have plugged each powered Hub into one port of the laptop.
Interesting I went into device manager and it shows I have 8 Generic USB hubs installed... Wtf. And also 2 x USB Root Hub & 1 x USB Root Hub (xHCI)
This is all weird....
Cgminer shows a total WU: of 4.5/m
The pool if I calculated it correctly is showing around 3000-4000KH for 20 Miners @ 361KH
If you're using comm port FIFO buffers on any comm & lpt port, not sure which program we're talking about, just jumped in...but I've been seeing some common complaints that have been addressed earlier in this thread that may or may not relate to 16550 UART FIFO buffers. If they are ON, turn them OFF!
No need for FIFO buffers with these things., It just causes some of the problems you guys are talking about.
Good luck!