Windows installer service cant start Error 193:0xc1 ???

Im getting the error when the windows installer service tries to start. Also
i Cant install any msi because i get the "The Windows Installer Service could
not be accessed.

In the event viewer I get the foolwoing error events:

The Windows Installer service failed to start due to the following error:
Windows Installer is not a valid Win32 application.

and I cant install any service packs for Visual Studio 2005

Can someone help please !!!

DCOM got error "193" attempting to start the service MSIServer with
arguments "" in order to run the server:
{000C101C-0000-0000-C000-000000000046}

[Ashburn]

Go to Add/Remove Programs for windows xp or Programs and Features in Windows Vista and uninstall the Windows Installer program. Then go to the Microsoft Website and reinstall the program. You can find the link to the Windows Installer Installation program here. Or you can follow the steps mentioned here.