VS2010 CTRL+M keyboard shortcut has stopped working

Question

I have a strange problem which seems to have recently appeared. I used to be able to press the keyboard shortcut CTRL + M + O to \'collapse

Answer 1

I have Skype installed. It had CTRL + M enabled for muting microphone.

Check all open programs and check their settings/options/preferences to see if they are using system wide shortcut keys and disable/modify accordingly.