How to fix registry modifications done by a messenger virus-thing?

i wanted to help a friend get rid of a messenger virus(or what it is) that keept sending mass messages for a month or so so i took it and managed to fix the mass sending and stuff but then i found out that it erased some of my browsers and changed and stuck my homepage but that was not so alarming ... then i saw that i have no more run button in the start menu and task manager was no more and regedit dissapered and also .reg files ar not recognised by my computer and i can't change file options like show extention or show hidden(witch were on before) ... and i think that's all but who knows what i'll run in to next ... anybody know how to fix this(without anything of what i sayd) or do i have to reinstall windows again?How to fix registry modifications done by a messenger virus-thing?
it has a simple fix. run system file checker

http://www.youtube.com/watch?v=ZiKmxSNFvHow to fix registry modifications done by a messenger virus-thing?
winkey+R regedit

this is the registry editor use it but be carefulHow to fix registry modifications done by a messenger virus-thing?
messenger is well know for worm virus, start in safe mode with internet %26amp; do a free online scan:



http://housecall.trendmicro.com/



When clean download %26amp; run the following:



http://www.comodo.com/boclean/boclean.ht



http://www.iobit.com/advancedwindowscare



http://www.ccleaner.com/