I am also experiencing this issue after upgrade to Edgy. PS2 keyboard works fine on bootup (BIOS, Grub etc) but post boot only the USB keyboard and mouse will work.
-- PS2 keyboard and mouse not working when usb keyboard/mouse connected (ubuntu.dapper) https://launchpad.net/bugs/49047 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs