I had a similar situation w/ my old LG phone when I upgraded to Windows 7 64 bit. I think it is an issue that the phone manufacturers haven't worked out with Microsoft yet, despite the fact that Windows 7 has been around over 1 year. No excuse for it, but I feel your pain. I resolved the issue by getting an Android phone instead.

BTW: My computer was previously running Vista but I had to do a complete re-install to upgrade to Windows 7. Don't think it has to do with your computer's previous configuration.