Not sure of the reason as it can be bas install or corrupted registry. You can edit the toolbar and add the tools you need. Right click on the toolbar and select customize from the list. Go to commands tab and then select sketch. Now drag the the tools from the right side and drop them on the sketch toolbar. After you are done click OK and save your file.
I had the same problem with SP1.0EV.
I've tried to replicate the problem with other installation, but the update has worked well.
So it's not replicate.
Rename SolidWorks registry doesn't resolve the problem.
The only solution is uninstall and re-install.