Bit of Ivory

My laptop has started acting up. Not hugely, but enough that it’s
annoying. You see, every once in a while the 8,i,k, and ,
keys stop working. All the other keys type, but that whole column
doesn’t work. So far, I’ve been able to get them to work again after a
bit, but there’s no continuity on what gets them to work again. The
first time, I turned it off for a while and when I rebooted, they
worked. The second time, I tried jiggling the comma key around, and
that worked. The third time, I got out a can of Dust-off and sprayed
out all the dust underneath the keyboard. I haven’t tried it again to
see if that solved the problem. I guess that’s what comes of buying a
used laptop.
However, I did go onto the Dell website and make sure the warranty was
still active and under my name. It is, so if anything goes wrong, I can
call up Dell. Hopefully it will be covered.
Wolf, any ideas as to what could be wrong?