The Add or Remove Programs shows a list of softwares installed in your computer. When you click the listed name of the software there are options which you can click for an action. The 'Change' option is used to repair the program, which means that exactly the same components from the original installation will be reinstalled. The 'Remove' option uninstalls the program.
Here's a step-by-step procedure to show the 'Change/Remove' button. Before proceeding, I urge you to create a system restore point because you will be modifying the registry. Please be extra careful.
1. Go to Start/Run
2. Type 'regedit' (w/o the quotes) then click OK;
3. Navigate to:
Uninstall\[Name of Software]
5. Double-click the 'NoRemove' or 'NoModify' entry and change the value to 0 (read: zero).
6. Close and then re-open the Add or Remove Programs in Control Panel and the 'Change/Remove' button will now appear.
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