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

Question

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?

note: i already removed the virus and cleaned the registry and everithing but that didn't get the run button and taskmanager or .reg file and regedit dosen't work

Answer 1

it has a simple fix. run system file checker
http://www.youtube.com/watch?v=ZiKmxSNFv0Q

Answer 2

messenger is well know for worm virus, start in safe mode with internet & do a free online scan:

http://housecall.trendmicro.com/

When clean download & run the following:

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

http://www.iobit.com/advancedwindowscareper.html

http://www.ccleaner.com/

Answer 3

winkey+R regedit
this is the registry editor use it but be careful