either my "advanced reply" has got lost or it is being moderated - so not sure if this will end up as a double post :-(

ATX MB do control ATX PSUs - this was the primary reason for the migration from AT to ATX.

Thereby it does not sound like it is a PSU issue although there are complex (to me) ways for a PSU to fail.

After an extended time not in use the CMOS battery that enables the CMOS to store critical info can have failed or discharged and hence the BIOS cannot read the CMOS to find where to boot from..

F2 is the normal Dell setup button, you need to get into the BIOS setup and check that your HDD are configured.

The POST is trying to tell you what is wrong, if you can track down the info on the Dell support web site for your MB.


Jon