Hi @netdudeuk
I’ve fixed with this issue a lot in the past with HP. The bios on many older models can get stuck and will need a CMOS battery reset. You can simply remove the button battery and re-install, but I would recommend replacing it. It would be a good idea to complete a BIOS update as well if one it available.
If this issue continues even after the battery is reset, it may be a sign of BIOS failure.