After upgrading to Froyo I found that every time I connected my Incredible to my PC, my browser opened a tab insisting I download V-Cast Media Manager. Verizon customer service said there was no way to disable this.
(Downloading V-Cast doesn't help: If you cave in and load V-Cast thinking that will stop the popup, Media Manager then insists on opening every time you connect your Incredible to your PC.)
Fortunately there is a way to disable this crappy tactic without downloading V-Cast. I got this fix off the Verizon Forum. It has worked for many people, including me.
On your Incredible, dial ##7764726
Press Call
At "Password," type 000000 (that's 6 zeros)
Press Feature Settings
Choose CD ROM
Click Disable
Press menu, commit modifications (it will say no item changed)
After doing this, I turned the DrInc off, then on again. I find that when I connect to my PC I still have all the USB functionality I had before, and my browser is no longer hijacked by V-Cast.