i have perfect solution to this problem without spending a penny...
while cleaning the keyboard of apple mac some liquid spilled in and some of the keys on the keyboard were working wrong. , the caps lock key was working vice versa to the normal function ...
what i did without opening the keyboard . i kept the laptop open under the fan.. dried it for a while and checked it .. '''there was not any change'''
and then next day my mac book was showing some updates to install which it does on regular basis ...''' i installed the updates and the keyboard was restored to its normal working condition..'''
'''u are right i found this solution accidently.....'''
for intalling updates
go to system preferences
select "software update" under system
now under the tab "scheduled check" press "check now"
the computer will come up with all the updates . make sure u get mac osx update aswell along with the other softwares or mac application.....
do try it .. m sure it ll help