I've posted this several times in various threads for people having trouble with windows not recognizing the phone or charging via USB after flashing to new rom. The fix for me TWICE was to use the app "quickboot", the third option down in the app is "bootloader" click that and your phone will appear to do a normal reboot. Once rebooted the USB will function normally again and remains good forever....no idea why but it just works.
Make sure usb debugging is checked of course and that usb is set to the proper mode ie mass storage. Hope this helps someone.