my computer wont work after installing avast....help?

hello, i need help…i downloaded avast and installed it today. my computer was working fine, but after i installed avast the computer doesnt let me shut down or open any applications. i do not know a lot about computers, anyone has any idea of what might be wrong? i had norton but since it expired i decided to get a free anti-virus…i did forget to uninstall norton before installing avast.

any help would be greatly appreciated!!!
thanks.

Download and run Norton Removal Tool.

Norton is the culprit, almost certainly.
Any AV should be completely removed (uninstalled then applicable removal tool run) prior to installing a new AV.

Do it as soon as you can then…

  1. Remove NAV or Norton 360 through Add/Remove programs from Control Panel. Boot.
  2. Use Norton Removal Tool for Windows 2000/XP/Vista or Norton Removal Tool for Windows 98/Me. Boot.
  3. Install avast! (or repair the installation) and boot.

The Norton Removal Tool uninstalls all Norton 2008/2007/2006/2005/2004/2003 products and Norton 360 from your computer.