I had v4 installed (the one form Comcast) and was informed of an upgrade to v5. I downloaded it and started the install. The first step was it removed v4 and rebooted. After the reboot the install started again automatically. When it was near the end the computer blue-screened (first time ever). Rebooted again, the install restarted again automatically and removed the existing v5 install. One more reboot, once again restarted the install. This time it completed normally.
First odd thing after the install: tried to download a Windows Gadget with Chrome 12, it just sat there waiting to start the download. After all gadgets were doing this I tried with IE9. It downloaded immediately.
Second odd thing: Tried playing Far Cry 2 through Steam. The opening movies start playing then the screen goes black. Waited 15 minutes but still no change. No keyboard combinations would do anything. Pressing power on the computer didn't shut it down immediately, which means the OS wasn't completely locked up. Had to press and hold power to reboot. Tried a couple times with the same result. Have not tried another game yet.
[edit: Clarified subject.]