no hard drive installed but it is installed

[Bobbygallon]

changed power supply. now getting error - no hard drive installed but it is installed

[Bill_To · Accepted solution]

Greetings @Bobbygallon 

Welcome to the HP Forum.

Since you changed the power supply you should reseat the power connector to the missing drive if it is a SATA drive.

Try a different power supply SATA power connector to the SATA drive if the PC's power supply and MB are standard ATX or uATX.

Or reseat the MB SATA power connection if your PC is not using a standard ATX power supply. SATA power comes directly from the MB to the SATA drive on some HP MBs.

Also check the data connections to the SATA drive and the MB.

Regards

[Bobbygallon]

Did all the other things. Replaced the power supply and that resolved the issue. Now there is a new issue.

The date on the CMOS is not holding. It keeps resetting. Any suggestions?

[Bill_To]

Greetings @Bobbygallon 

Good to see you resolved the first issue.

Your Desktop PC probably needs a new CR2032 MB battery if it is having date and time problems, and other BIOS configuration retention problems.

A RTC chip problem could exist if changing the MB battery does not help.

Regards

[Bobbygallon]

Changed the battery and got the same problem. Not sure what is meant by - "RTC chip problem"

[Bill_To]

Greetings @Bobbygallon 

There is a separate chip (CMOS), usually located in the Southbridge chipset area, on modern MBs which retains date/time and modified BIOS settings.

This RTC chip is powered by the CR2032 MB battery.

It looks like your PC's MB  may have some type of RTC chip (CMOS) related problem (failing chip or a MB power rail problem to the RTC chip) if a new CR2032 MB battery is not powering the RTC chip.

Regards