Go to the following registry entry:
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\DevDiv\VS\Servicing\9.0
Set "SP" value to "1"
Set "SPIndex" value to "1"
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\DevDiv\VS\Servicing\9.0\RED\1033
Set "SP" value to "1"
Set "SPIndex" value to "1"
Set "SPName" value to "SP1"
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\DevDiv\VS\Servicing\9.0
Set "SP" value to "1"
Set "SPIndex" value to "1"
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\DevDiv\VS\Servicing\9.0\RED\1033
Set "SP" value to "1"
Set "SPIndex" value to "1"
Set "SPName" value to "SP1"