DELL WINDOWS XPS 400 SYSTEM RESET

I am assuming from what you have described that you enabled the BIOS password.  In other words when the system is first booted up you need to enter a password before the system will load Windows.  If so there is a jumper on the motherboard that will clear the BIOS passwords.  You can click here

for the XPS 400's on-line Service Manual and the section pertaining to clearing the BIOS password.

hey1 thanks i was able to get my system back but 1 more thing now my philips dvd+-rw dvd 8801 is not reading any type of disk i unnistalled and reinstall but still does not work i diognost my system and it says is working propperly i no what else need to be done i also check my system conf and is enable well thanks if you can help me!! ist because i updated my BIOS to 007

 

If the problem with the optical drive started right after the BIOS update then I would suggest clearing the CMOS.  After a BIOS update it is not uncommon for there to be conflicts between the newly installed BIOS version and the installed hardware.  By clearing the CMOS the system will redetect all the installed hardware and default all your BIOS options back to their factory recommened settings.  You can click here for your model's on-line Service Manual and the section pertaining to clearing the CMOS.

 

In the event after clearing the CMOS you get an error regarding the diskette drive on boot up and you don't have a floppy drive then just go back into the BIOS Setup.  Turn Off the option for the Diskette Drive and the error message will be gone on the next reboot.  That option can be found in the Drives sub-menu.  The reason this occurred was that clearing the CMOS defaulted all your BIOS options back to their factory settings. On some models this defaulting will turn on the Diskette Controller even though there is no floppy drive in the system.