Spiro Harvey wrote: >> The message on the screen tells me to look at the System Event Log. > > What application is doing that? System Event Log sounds like Windows > terminology. Centos-5.2 halted, and the message on the screen told me to look at the System Event Log. In fact I found that on pressing F2 (Enter Setup) on boot I was given a list of options, which includes System Event Log. Pressing this allows me to read entries going back several days. In my case I found the error "Uncorrectable ECC Error DIMM 1,1". On swapping the two 2GB memory modules, the message changed to "Uncorrectable ECC Error DIMM 2,2". This seemed to me to be pretty strong evidence that the fault was indeed with one of the memory modules. Unfortunately it was difficult to convince Dell of this. The technical support man I spoke to (in Scotland) claimed that it might be a software error caused by installing Windows XP Pro as a second OS on the machine. He asked me to run a diagnostic test which in fact did not run because I did not have the "Utility Partition" that it required. In the end he agreed to send a new module in place of the old one. >> Incidentally, wouldn't it be a good idea for /var/log/messages* >> to start a new file when booting? > > that's what /var/log/dmesg is for. As far as I can see, this only contains messages about the boot sequence? In any case, it did not contain any messages relevant to the crash.