To cleanup the C:\windows\installer directory if it is too big,

Use the msizap utility (install the Windows install cleanup utility “MSICUU”: http://www.commentcamarche.net/download/telecharger-34072617-windows-installer-cleanup-utility, msizap.exe is on the install folder)

msizap G!

Technet reference : http://msdn.microsoft.com/en-us/library/aa370523.aspx

other interesting link: http://www.symantec.com/connect/articles/windows-install-clean-utility-using-msizap