Ubuntu server 9.10 freezes up after ~10 minutes

I just upgraded my Ubuntu server from 9.04 to 9.10 and after about 10 minutes it locks up. It won't respond to ping, can't ssh in and the terminal doesn't accept keyboard input. It does not have X installed. I then reformatted and installed it from scratch with the same results. There are two hard drives, the first is for the OS and the second is for media. The second has not changed, it is an ext3 formatted drive with one partition.

I stopped random services (samba, ushare, transmission-daemon) to see if they were causing the issue, but it still locked up. I did a watch "dmesg|tail" until it locked up, but I didn't see anything.

How can I troubleshoot this further? I don't want to downgrade.

Machine specs: Dell Dimension 3000 Pentium 4 @3GHz 512M RAM

I had the same issue with Ubuntu Server 9.10 (headless setup, Intel graphics). Adding nomodeset option to /etc/default/grub worked fine for me. Don't forget to run

$ sudo update-grub

after all.

Another option is to disable the framebuffer support by adding the nomodeset kernel option in /etc/default/grub:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash nomodeset"

The box has been up for more than an hour since disconnecting the display now.

edit: After a day I can certainly confirm the problem has been solved by disabling framebuffer

Have you ruled out a hardware issue? I'd suggest trying booting with a 9.04 livecd and leave the computer running for a few hours. If the problem disappears, it's probably a bad driver in the 9.10 kernel or similar.