[fgr]

I had the same problem, stumped me for days... Here's what I did.

Connect with activesync. Then start internet sharing. Wait for the three "dongs" from your computer.

Then on your computer, open up the the control panel and select the system icon. Then go to the hardware tab and click on device manager.

Once there look at the network adapters. The one for your phone will probably have the yellow exclamation point next to it because it is disabled.

Simply right click on it and select enable. Should work fine now.

Let me know if this helps.