Josh, Can you run these 2 updates and see if that resolves the issue? They do call for a reboot.  BIOS -  www.dell.com/.../DriverDetails ESM -  www.dell.com/.../DriverDetails
Our server at my client's business (Dell PE2500 SBS2003 SP2, 2GB RAM) has been becoming increasingly less responsive. Random hard drive failures, unreponsive behaviour etc. After scouring google for a few hours, i installed the DSET report. the following is the voltages output. 
PE2500 problem