Help! Pressing Tab no longer works for accessing my configuration menu

*I am new to the site, I apologize if this topic has been covered before*

I am not sure what I could have done to disable this feature. When I press "tab" nothing happens. I have been using this version (mame32 0.69) for years and all of a sudden I can no longer access the configuration menu to map my buttons and joystick. Any suggestions? Thanks

Thanks for the suggestion Jason. I actually deleed the config file and was able to get everything back to normal.