How to obtain an uninstall string from the registry for an application listed in add/remove programs

Under “HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\” there are a number of product GUIDs listed, eg, {6BB9FB92-93A6-4763-8 D 15-DEB4D5433030}. Look through each of these, looking at the “DisplayName” key, to find the software you want to uninstall. Once found, there will be another key called “UninstallString”, and this has the command required to uninstall the product, eg, MsiExec.exe /I{6BB9FB92-93A6-4763-8 D 15-DEB4D5433030}
NB: the “DisplayName” key is also what is displayed in “Add/Remove Programs”

Edit: Another way to find the required GUID is to open up Component Services.

1. click on "start > run", type in DCOMCNFG, and press Enter
2. Expand the trees "Component Services > Computers > My Computer"
3. Click on the DCOM Config folder
4. In the right-hand pane find the application you are looking for, the GUID for that app is displayed next to it.