On my HP Pavilion n5210 notebook the asldfjk keys stop and start working. I restored windows and the problem did not go away. Does anyone know how to fix this problem?

It's possible that it's just a bit dirt in those keys. I just had it on an old 386 notebook from a friend. Try to remove the keyboard caps with a srewdriver (hook the tip under the cap and carefully apply a little pressure to the top by using the key below as some sort of lever. The cap should come off easily so don't use too much force because you surely don't want to break something. Next remove the spring and blow it out. If something sticks in it carefully remove that with the screwdriver or a q-tip. Then try the key with the screwdriver to see if it now works. If ererything is fine put the spring in and put the cap back on. Check that it fits properly. If that doesn't help the keyboard maybe broken but mostly it's just dirt!