When I shut down the computer, then turn it back on- everything goes fine- system loads, no errors.
BUT
When I am in a turned on system, and I ask it to restart (reboot), when the machine restarts and the system starts loading- I get a kernel panic. Every single time- but only when I ask the machine to restart.
If it helps, the error didn't appear on Fedora 14.
To make it more colorful- the same situation happens with my Ubuntu 11.04 (I have triple boot- Fedora, Windows and Ubuntu- I am learning Fedora to switch from Ubuntu). When I had Ubuntu 10.10- all was ok- when put 11.04- the error is the same- I can't restart my PC properly. The only system that loads as it should every time is Windows 7.
Could anyone pls help me? My guess is that it's some kind of kernel change, because the error didn't show up in the previous versions of both systems (Fedora and Ubuntu).
Did memtest (after 12 passes there were still no errors), tried acpi options, modeset, nomodeset (using grub2)- all for nothing...
I hope together we can solve the problem!

If U need any logs, U have to tell me how to get them- still a newbie for Fedora ^^
Cheers from Poland, Kuba