i've been down this path once myself about 1 - 2 years ago. But luckily, for my case, it ocurred on a machine i just use for testing as well as had recent full backups/ghost image of the disk.. So for my situation at the time i was able to investigate, understand what was happening and pin down the culprit.
So here;s the deal...
1. Information about installed programs along with info telling windows what installed programs to display and whether to show Add and/or Remove buttons are all kept in the Windows registry. (And, yes, that means you can have installed programs which
by design don't appear in Add/Remove).
2. So first thing is checkin if a) something might have changed all those display options or b) something simply ERASED all that information from the Windows registry. Try running
MyUninstaller. It basically ignores the display options and shows you all the detail in the registry.
- If programs show up using MyUninstaller, the info is still there. But display options have been changed
- If nothing shows up, something has erased the registry data
3. If data has been erased, you have limited options
- Try a system restore point (and try soon as they "expire". Windows reuses the space when it eventually needs it for a new restore point)
- Look to see if an uninstall.exe program exists in the folder where the program was installed. If a program's uninstall process is simple you might just be able to invoke the uninstall program and the uninstall completes. However, if its uninstall process requires arguments passed to the uninstall.exe and/or other data is required for a proper uninstall, that's the info that was kept in the registry when it was erased! So try uninstall... may or may not work correctly.
- Try to install program again. Use repair option if it's offered. This usually restores the program info in the registry.
4. Finally, by chance, did you recently uninstall Yahoo Browser Services? For my specific situation way back when, that was responsible for the screw-up. Am sure malware or other buggy programs might do it as well