The Windows Installer Service Could Not Be Accesed.

Hello everyone i recently started having errors unninstalling programs.When i try to unninstall something the error <<The Windows Installer Service Could Not Be Accesed>>Pos Up.I am also having problems installing some games NOT from this site.The wierd thing is that this dosnt happen to some installers cause i could Install Fallout:New Vegas and Unninstall Race driver Grid.I hope some body can help me.THANKS!!!
OS=Windows 7 Ultimate 32 bit version.All Drivers are up to date.
Answer #1
you could try this Log on to your computer as an administrator.
Click Start, and then click Run.
In the Open box, type cmd, and then click OK.
At the command prompt, type msiexec.exe /unregister, and then press ENTER.
Type msiexec /regserver, and then press ENTER
or fix 2 , try this download this 1.http://www.winhelponline.com/blog/wp-content/uploads/msiserver.zip
2. Unzip the file and extract msiserver.reg to the Desktop.
3. Right-click msiserver.reg and choose Merge.
4. Click Yes when asked for confirmation.
5. Restart Windows.