BIOS problem - computer does not boot.

Hi all,
I have a desktop Dell XPS 400 DXP051 with the following features:
1) Phoenix ROM Bios Plus Version 1.10 A07.
2) Windows XP PRO SP2.
3) Processor Intel Pentium D 830 (3GHZ) Dual Core, 1 GB RAM, 250 GB HD. It does not have floppy diskette.
Two months ago it started to give us problems to boot, we had to push the power on switch many times to get the power on. We thought that the cause of this was due to lack of memory and we upgraded to 3GB but the issue still remains. This morning I run a diagnostic from Dell Resource CD that took 7 hours to finish and the result was good, all the tests were passed.
I want to give you guys the messages I got every time I reboot:
Alert! Error Initializing PCI Express NIC Bridge
NIC failure
Floppy diskette seek failure
Strike the F1 key to continue, F2 to run the setup utility
I had used the option to LOAD DEFAULTS, and even though we do not have floppy diskette we got the above mentioned message.
I tried to update/repair  the operating system with the CD provided by DELL and I got the mesage:
Windows XP Professional Setup
Setup cannot find a CD-ROM Drive.
Make sure your CD-ROM drive is on and properly connected to your computer. If it is a SCSI CD-ROM drive, make sure your SCSI  devices are properly terminated. See your computer or SCSI adapter documentation for more information.
Setup cannot continue. To quit  Setup, press F3.
Trying to get a solution, I download the XP051A07.EXE, that is an update for BIOS. I copied in my flash drive from my laptop and I took to the desktop Dell to update the BIOS, but the computer shutdown itself and now the computer is not able to boot. It seems like the BIOS did not finished to get updated and got corrupted.
Is there a way to restore to the default firmware settings without a floppy diskette and no booting at all? According to the log I have repored what I can do to fix this computer and I need desperately help. Thanks in advance.