[help] gsc editing

hey guys i have windows 7 and for some reason when i try to edit my rank.gsc it wont let me..if i try to change it to something different like a .zip file it will let me but it wont let me change it back...when i rename it back it just changes the name back to .gsc but still opens with whatever i changed it to open to so that i could edit it...but i can view the file and change it to.gsc and .zip an winrar but it wont let me change any of the coding in the files it just lets me view it...if you guys could help me out thatd be great thanks

Start > Control Panel > Large icon view > Folder Options > View > Un-tick 'Hide extensions for known file types' > OK.