itunes update would not install due to an error, now itunes won't run and I get this message when I try to launch itunes: "This application has failed to start because MSVCR80.dll was not found. Re-installing the application may fix this problem"

itunes update would not install due to an error, now itunes won't run and I get this error message when I try to launch itunes: iTunes.exe - Unable to Locate Component "This application has failed to start because MSVCR80.dll was not found. Re-installing the application may fix this problem."

I'm on a Dell PC running Vista Home Premium.

HELP!!!!!!!!!!!!!!!!!!!