You might have had problems with Excel prompting for a CD in order to install some add-on, and like most of us without that CD, Excel will abort and all a sudden you can't use Excel anymore on the machine.

<rant>That a patch loading process goes as far as preventing someone to use an application goes beyond stupidity. Somebody lynch/burn/percolate the guys at Microsoft who have decided that customers would benefit from this kind of behavior.</rant>

Now for the solution. There are basically two ways to fix the problem. One involves access to the Windows registry which may not be possible for you if you are not running with admin privilege. Also you should make changes with extreme care because the registry could damage Windows altogether. The other is very easy to put in place, does not require admin privilege, so is perhaps the most suitable.

1) Fixing the CD prompt problem by modifying the registry

Open the Windows Start menu, click Execute, then type "regedit" and hit enter. Expand the following node : HKEY_LOCAL_MACHINE, Software, Microsoft, Office. At this point, if you have installed Excel 2000, then expand node 9.0. If you have installed Excel XP, expand node 10.0. If you have installed Excel 2003, expand node 11.0.

Beneath this node, you should find one called "Delivery". If you don't find it, then abort the work with the registry and go to tip 2 below. Otherwise, expand this node, and then, for all nodes of the form {90110409-6000-11D3-8CFE-0150048383C9}, click on those nodes, edit the value on the right hand side called "CDCache" by right-clicking on it and select the appropriate option, change the value to 0, and click enter. Iterate with all of these nodes.

Close the registry tool, you are now ready to use Excel again. Note that under the same principles you should be able to skip prompts occuring with Word or Powerpoint.

2) Creating a shortcut to the application

An easier way to fix the problem is to simply create a shortcut to the application, then use it any time you want to start Excel instead of using the existing shortcut provided by Microsoft in the Windows Start menu.

To create the shortcut, right-click on the desktop, choose "New", "shortcut". Then find the Excel application installation path by browsing the folders. Hint : you should start at C:\Program Files\Microsoft Office, then proceed with Office subfolders whose name depend on the version of Office installed, then eventually you should be able to reach Excel.exe. Note that the same mechanism allows to skip CD prompt problems with Word.exe and Powerpoint.exe.
Click Next in the shortcut wizard, then Finish.

Now you can start the product without getting prompted anymore.