I was having trouble on the first install/upgrade that I did on My desktop, so I had to call Microsoft. Gotta take advantage of the free support while you can. The tech was very helpful and stayed on the phone with me through the entire install, even while I was downloading my audio and video drivers. I give Microsoft tech support an A++
The tech walked me through the exact same steps as noted from the link from above. There was something on my harddrive that Vista didn't like.
After you skip the product key entry, and select custum instead of upgrade, this is were you can re-format your harddirve and start clean. So the first initial clean install will go very quik, then when you re-install for the upgrade and add your product ID in there. Then it will take about 10 - 20 minutes longer, but still pretty quik.