Installer or uninstaller are freezing after upgrading to vista

Hi,

I upgraded my laptop from Vista home basic to vista business. Everthing
went fine. I started uninstalling SQL server express and installing SQL
standard edition, this version never ended. I force to restart my computer.
Since then, I am having problems like I cannot install or uninstall any MS
softwares. The installers are giving error message "Instal server not
responding" after couple hours. Cancel is not closing the window, it will say
cancelling the installer.

Somehow, I managed to logging with Administrator account and found the
same problems. IE also freezing, When I tried to install ActiveX components
from MS website to apply some fixes from MS knowledge base.

Please help me to fix this computer.

Thank you

Uday