While doing some testing I managed to corrupt at least 1 32-bit application layer networking dll on Win7 64 bit Home Premium (upgraded from Vista).
I can use the 64 bit networking applications fine (IE etc) but any 32 bit networking application cannot get out. Connections to modems are fine, as are the drivers (ping, telnet using CMD works fine).
As a result, my next step seems to be to attempt a repair on this system (the restore point available to me is from after the corruption occured). However, since I have a machine that was upgraded from Vista to Win 7, all I have is the upgrade CD. That CD does not have a repair option when I pop it into the drive and I am leery of using a Vista Installation CD to repair the 32 bit comm stack.
How can I attempt a repair in this situation?
Use a 64 bit Windows 7 .iso as here, either use one to repair install or clean install as instructed here. They will fine with your upgrade product key.