Dell XPS T700r Loops During POST

I received a Dell Dimension XPS T700r, which has been updated with BIOS A08, in January 2000. The software is Windows 98 2nd Edition and IE 5.0.

The following seldom happens. A few times when I power on the PC, it goes into a loop. This is even before booting the operating system. It displays the following messages (not exact wording and may not be exact sequence):
Init MBA
Managed PC Boot Agent 4.0
System configuration updated
Press Alt-Ctl-B to enter (unknown)
Operating system notfound.

The only way to break the loop is to power off and then on. Even the ?reset? button will not help.

I would appreciate any assistance. Thank you.