command key stuck

Guys,
Have had numerous problems with lion after the update, and it's getting really annoying to me.

one thing that i bumped into today is that somehow, whenever i hit the command key, it is locked, i have to press twice in order to unlock it. also, there is a command key sign on the screen.

anyone has had the same problem?? please help!

 

problem solved.... turn off stick keys in the universal access. never had this problem after 6 years with mac os. just weird...