Although System Restore is designed to put your computer in good working order, sometimes the process isn’t perfect. It sounds as though you might have a corrupted file since you can’t uninstall any of your programs.
Uninstalling Programs
Typically, the Add/Remove utility in the Control Panel is used to uninstall programs. If it isn’t working, then the appwiz.cpl file is probably missing or corrupt. In order to use the Add/Remove utility or to uninstall programs that you no longer want on your computer, the appwiz.cpl needs to be in place. If it isn’t, then the situation will generate problems uninstalling programs.
Clean and Repair the Registry
With the possibility that you might be able to clean and repair the registry without having to modify it manually, perhaps you might want to use a registry cleaner. This type of application will perform an automatic or manual repair. One program that I can recommend is RegCure. It is designed to repair your computer’s registry. Plus, it has a built in scheduler and a backup and restore feature. It shows a view of the scan’s progress and offers easy customization.
How to Restore the appwiz.cpl file in Windows 95 and 98
Microsoft’s support section has a detailed explanation on how to restore the appwiz.cpl file if you have Windows 95 and 98. Read through the article and follow its instructions in order to restore your Add/Remove Utility.
How to Restore the appwiz.cpl file in Windows 2000, 2003, and XP
In order to restore the appwiz.cpl file so that you can uninstall unwanted applications, read the article located at Support Article 266668 and follow the instructions very carefully since you need to modify the registry.
How to Restore the appwiz.cpl file in the Command Prompt
Another possible fix for this problem would be to place the missing appwiz.cpl file back where it belongs. Follow this set of directions:
1) Click “Start.”
2) Click “Run.”
3) Type “cmd.”
4) Click “ok.”
5) Type “regsvr32 appwiz.cpl.”
6) Press “enter.”

Insufficient Storage Available Error
Congratulations on your new Vista computer and for not listening to all of the scare stories. I have Vista running on one of my machines and once you get used to the interface, it can be quite enjoyable. The Windows Aero display is a great way to keep track of several things that are running at the same time, and it gives you great entertainment and research options as well.