Dell OptiPlex 745 reboot problem -- BIOS update went poorly

[Jonathan Underwood]

2008/9/5 Johnathan Hegge <johnathan.hegge at bluecoat.com>:
>
> Ugh, I was having the same problem with my 745.  So, I drug out a USB
> floppy and applied the latest BIOS -- going from 2.3.1 to 2.6.2 from
> Dell.  Whoops.
>
> Starting up looks fine, all services showed OK.  Gets to local, X starts
> and the box freezes at the spinning dots with a frozen mouse.  Can't
> break with Ctrl-Alt-Del or Ctrl-Backspace.
>

I have a couple of the optiplex 745 line running Fedora (from about 6
upwards to 9 currently) and have upgraded the bios from
2.3.1->2.4.1->2.6.2. At no point did I see the problems you're having.
Makes me suspect you have a hardware fault somewhere - have you tried
running memtest overnight?