When you say it would work when you click the icon, do you mean the shortcut icon to the program or the icon for the words/excel/powerpoint file?
Well anyway, if it is the program shortcut icon, then there is a target problem with the shortcut.
Right click on the shortcut>properties and change the target to the programs current installation path.
If it is a file shortcut, sounds like a file association problem.
Right click on the words, excel, power point icon and select open with>default program
Select the program it should be open with (may not be in the recommend program list and so you may have to click the browse button to look for the program). Tick always use the the selected program to open this kind of file. Ok.
You can just pop the Office installation disc in and do a repair installation.