webcam not working after bad touchscreen install

hello all,
after reading all the posts about how great the touchscreen mod is, i decided to go ahead and do it. unfortunately, after getting everything all connected and powering the machine up, the new hardware wasn't being detected (no "windows found new hardware" window and the software that came with it wasn't detecting it either). my webcam also wasn't being detected at all, as if it had disappeared. this made me think that it might be a faulty unit so decided to uninstall it.

i uninstall it and now whenever i try to use my webcam, i get either a message that says that the webcam should be connected to a hi-speed usb 2.0 port (and i don't get any image), or i get no response at all (although now it is listed in the device manager and under "devices and printers" in the control panel). i also can hear the sound that plays when plugging in a USB device before it gives me the message about not being connected to a hi-speed usb port. i've tried a few things...

1) check to make sure wiring harness to webcam is secure
2) delete the webcam driver and USB drivers from device manager
3) reinstall windows!

and none of the above worked. i'm running windows 7. any suggestions would be greatly appreciated...

thanks for your time..