Dell Latituded600 problem:windows installer

Could somebody please help me out?? I have problems when trying to download the newest version of messenger, which is messenger LIVE, a message apperas: error, something is wrong with my windows installer code 1601. And so I can’t download the newest version of MSN, and many other things. And wehen trying to delete my old msn, which no longer works, I can’t do that either, and the same message apperas: error 1601.
HELP please!!!