Fixed my problems Bluetooth pairing iPhone 4 w/PC...
In case anyone else has this problem, after a ton of research on many forums plus trial and error, here's the info that helped me, in case it can help someone else...
I kept have problems trying to pair my VZWiP4 with my Dell M4400 running Vista Ultimate x64.
The phone would sometimes pair, then other times not be recognized at all.
Also, I kept getting a device error because it couldn't find the right device drivers to install, since neither Apple nor Dell provide any for BT pairing iP4 to PC.
Basically, my problems were that my Wireless Router was too close to my iP4 and PC, causing interference with the BT connectivity, and I needed to download a Microsoft driver for mobile devices to eliminate the error message I was getting when Vista couldn't find a BT driver for the iP4.
The discussions in these two links were extremely helpful:
Apple - Support - Discussions - I can't connect
Solved Bluetooth peripheral device driver solution - Windows 7 - Windows 7 Forums
Apple - Support - Discussions - Windows Vista claims for "Bluetooth ...
GUIDE: iPhone Bluetooth Tethering on Windows Vista
This was driving me nuts so hopefully it will help someone else.