Quiet installed applications do not appear in the Add/Remove Programs Applet in Control Panel whereas Display installed applications do. You can ignore it or you can use regedt32 and go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall which has subkeys for each application installed. Non-microsoft programs will have a key UninstallString or QuietUninstallString which points to the uninstall program while key DisplayName should let you know to which application the keys belong.
I suggest running the uninstall program referenced and if that fails, (often will), just delete the entire subkey for the application. Just clean up the application's directory. If there was not a working uninstall, there probably will be orphaned dlls in the win32 directory. I usually ignore these things and when I get peckish, go in and delete their registry keys. I also reinstall my workstation more often than I want to also. There is a price to be paid for being peckish.
An alternative is the freeware utility Add/Remove Pro which displays the entries in the Add/Remove Programs list of Windows Registry, checks if each is valid, and uninstalls the selected program or removes the entry from the list.