Details: Ubuntu 11.04 BETA I fails to allow use of Unity Desktop when a nVidia GeForce Go 7300 is used.

Problem: The new nVidia driver introduced with Ubuntu 11.04 is not actually compatible with said card.

Solution: Simple.
First, to get into some kind of desktop, get back to the Ubuntu login screen (you can NOT get the desktop to un-freeze, you may have to force shutdown or do some other complicated things).
At the bottom of the login screen, select a different desktop to use. The drop-down box is set to Ubuntu as default. Instead, select “Ubuntu Classic (no effects)” and log in.

Your desktop should now load with the traditional Gnome interface. Don’t walk away just yet, as full functionality is just a moment away:

Open (under System) “Additional Drivers”, find whichever nVidia driver is installed and remove/deactivate it. Restart your computer.

Login and open Additional Drivers again, and install/activate the driver named “Expiremental 3d Support for  nVidia cards”. Restart your computer, and change the desktop in the login-screen drop-down box back to Ubuntu.

Ubuntu 11.04 with the Unity desktop should load successfully.

Please comment if this post worked for you, as well as other solutions you may have found.