By default Microsoft doesn't allow Windows Installer service to run in Safe Mode\Safe Mode with Networking to make sure no virus\spyware get installed on the machine while you are working in Safe Mode.
The name "Safe Mode" itself gives you an idea that you machine is running in a more secure enviroment eliminating all the 3rd Party drives, services and other utilites. An operating system in safe mode will have reduced functionality, but the task of isolating problems is easier because many non-core components are disabled (turned off) and if we add the basic network components to the safe mode to get the connectivity over the LAN we call it "Safe mode with Networking".
1. Safe Mode
2. Safe Mode with Networking
Now lets do the real magic and make you install\uninstall applications in safe mode:
1. Boot the system in safe mode by pressing F8 while booting up the machine and select safe mode.
2. Login with administrator account.
3. Start | Run | Regedit (To open registry)
4. Browse to registry key for safe mode or safe mode with networking. In this scenario we will choose safe mode option but don't you worry the following steps are same if you want to run windows installer service in Safe mode\Safe mode with networking.
Safe Mode with Networking
5. Right click on Minimal key and create new key.
6. Change the new key name to "MSIServer".
7. Now go to Start | Run | Cmd and run the command Net start Msiserver.
8. Now you can install or uninstall any application.
This way you can run any service in safe mode unless and untill its dependency service are running.
Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
How to back up and restore the registry in Windows, KB 322756