Only way my system may have been compromised was through sendmail ... which I have chosen not to install on FC5, but was there on FC4.
Prior to this crash I updated the system as usual ... yum update --exclude=kernel (I was running an older kernel to stay away from the ambiguous "..MP-BIOS bug: 8254 timer not connected to IO-APIC" error). I also messed around a bit with the grub.config adding the noapic flag to the newer, buggy kernel ... I think this may have a lot to do with it. It booted fine with noapic the first time ... the night before it screwed up, then I removed the noapic, and it also booted fine, and then it didn't boot fine in the morning.