Have you recently installed any new Windows Updates?
Do you have any anti-virus programs or firewalls on your computer?
Are you able to get online? I know you posted here, but perhaps it was from a different computer.
Do you see any error messages when you try to open any of those things?
Try Holding down you windows logo key on yor keyboard and then pressing the letter R - It will open a run box on your computer.
Type into the run box: APPWIZ.CPL
This will open the add/remove programs window - if it doesnt, either your windows installation needs repair or something is blocking it
Please post the answers to the questions I asked and the result of the Step I want you to try.