I'm new at this so I'm learning my way through it and I'd appreciate any guidance. My system freezes solid intermittently for no apparent reason. The serial console shows a kernal panic caused by a machine check exception. mcelog decodes the MCE as follows: CPU 0 4 northbridge TSC f03d1e587b Northbridge Watchdog error bit57 = processor context corrupt bit61 = error uncorrected bus error 'generic participation, request timed out generic error mem transaction generic access, level generic' STATUS b200000000070f0f MCGSTATUS 4 That's all meaningless to me so I'm looking for help understanding what it means and what parts of my system I should be looking at in order to try to resolve this MCE. A Google search found one hit that suggested that "Something tried to access a physical memory address that was not mapped in the CPU." If that is indeed the correct interpretation, is there any wany to figure out what that "something" is? The system in question is a no-name system built from parts by a local computer shop. It has an ASUS A8N-SLI motherboard. I have updated the BIOS to the latest without affecting this problem. The CPU installed is an "AMD Athlon(tm) 64 Processor 3500+". I am running Fedora Core 4, kernel 2.6.12-1.1398_FC4. Any guidance would be appreciated. -- David King dave@xxxxxxxxxxxx