how to kill this process?

[R Kimber]

I have a process taking up 100% of CPU:
29477 root      25   0  7024 1516 1112 R  100  0.1  52:48.84 sh

but I don't seem to be able to kill it.  I assume its being run by cron:

29476 ?        S      0:00 /USR/SBIN/CRON
29477 ?        Rs    49:20 /bin/sh -c    run-parts
--report /etc/cron.hourly

I've tried -9 and -15  - is there anything I can do to kill it, or must
I reboot?

Thanks
-- 
Richard Kimber
http://www.psr.keele.ac.uk/