Red Hat / Fedora :: Keyboard Not Working In RHEL5?

in order to select multiple items, shift key was hold for several seconds[sure > 8sec] and there after system is not taking any input from keyboard. however only the mouse works. i searched a lot and found some remedies like hold right and/or left shift keys for 8 sec and it will revert back. press shift key 5 times and hold ins key for 8 sec etc,. but i tried all these and none of it seems to be working. i even hold some alphabet key for 8 seconds to see if it takes input, but none of them seems to be working

i connected this keyboard to other machine and it works fine. this keyboard is USB dell keyboard. i tried logging in init level 3 and even with this i can not input anything from keyboard. i did reboot several times and unable to even login as it does not take any keyboard input. the only way i can access this system is to remote login from other system and work on command prompt!!is there a fix to it? accidentally if something is changed in which file it is saved? can i edit that file and restore to normal? am not sure if all these does not work i may have to reformat!! but this is the last thing i want to do