This is the single most infuriating issue I have with Windows ever since XP. I recently built a new system and bought Windows 7 32bit.
I am an electrical engineering student and I have a whole host of development kits and trinkets that connect via USB and the virtual com port drivers. Some use the FTDI chips for the interface and other use a Pic or AVR chip for it but either way their is an issue with Windows 7 and the CDC driver process.
I have a PIC running as a serial bridge. The device works perfectly fine on my XP machine so I know their is no hardware concerns. Below is the INF that will install on XP without any issues at all. mchpcdc.inf
Windows XP has usbser.sys in its drivers folder at OS install so the stock INF works for that system. On Windows 7 its in the driver catch and you must use the commented changes to make it found. This is the way the internet recommends and this works on a Vista computer at school.
This might work on Windows 7 except my device shows up in the hardware manager as an "Unknowen Device" under "USB Controllers" and when I manually point it to the INF above it simply says "Does not contain a software driver for your device" and setupapi.dev.log does not even output anything other than that same message!
I tried "Add Legacy Hardware" and that loads the driver exactly as it should but the driver is not actually pointing to any hardware. When I unplug the Pic the legacy device stays listed and when you open it in TeraTerm it can not connect to that com port.
Does anybody know how to force feed Windows 7 these drivers as I have about 5 devices I use on a weekly basis that do exactly the same thing!!!