I have 3 days ago installed succesfully a new harddrive,but today I booted up my PC and it says "Keyboard Failure",but the mouse and all other USB things don't work but it works on other PC's. I can't do anything on my PC and I'm asking for your help
EDIT: I'd forgot to say that the USB ports on the front panel don't work to.
double check the pins to the front panel USB ports. If the pins are not right, they might disable the USB. This could have happened when you put the HDD in, those pins/cables dont stay on very well sometimes.
if you frequently use the USB, and it gets a little bent every now and then, it may have broken the USB port. It sounds like the ports are broken, maybe you should get a service center to look at it? I doubt there is anything you can do other than some soldering.