If you upgrade your Fedora 15/16 to Fedora 17 before it is officially released, there is a high probability that you encounter a bug, where your computer receives a kernel panic when you try to shut down/reboot. This is documented in bug 820351. The problem is that since Fedora 17 updates repository is still not open, your system might still have an older kernel installed. To fix this issue, just install the latest kernel from Fedora 17 updates-testing repository, like this:
$ yum update kernel\* --enablerepo=updates-testing
After one more reboot, your system should be fixed.
Please note: This bug should not appear once we officially release Fedora 17 (a.k.a GOLD), so that extra step won’t be necessary.
EDIT: The problem persists even in final release and different steps are required.
Kparal's Fedora Blog 
Updates opening won’t help at all because the DVD does not use them when upgrading.
Oh, you are right, the issue will be fixed only if you use preupgrade (which I silently assumed). If you use DVD to upgrade, you will see it even after Fedora 17 updates repo is open. That is unfortunate, I agree. But once the updates repo is open, one “yum update” (or update through GUI tools) will fix it, the extra step mentioned in the blog won’t be necessary.
I just upgraded to fedora 17 using preupgrade. I have this same issue. Unfortantley, the command did not resolve my problem (No updates were found)..
same
no funciona!!
unfortunately your fix not working on my laptop after upgrade from FC16 to FC17 and fail boot with kernel panic 😦
I can’t update my FC17 after upgrading from FC16 using DVD. Also I can’t power off my PC for kernel panic problem. Please help me to find what my problem is.
https://bugzilla.redhat.com/show_bug.cgi?id=820340
https://bugzilla.redhat.com/show_bug.cgi?id=820340 – looks like you might need to update the /etc/grub2.cfg file and update or add the new FC17 kernel grub entry. Appears there is a bug in the installer.
i had the same problem, and that was the solution for it:
http://linuxfordummies.org/preupgrade-from-fedora-16-to-fedora-17-boots-to-old-fedora-16-kernel-issuefix/