Only one memory slot reading why?

[Mudloff]

I have 2 memory slots but only 1 is working .What do i do?

[Bill_To]

Greetings @Mudloff 

Welcome to the HP Forum.

How did you discover a memory slot is not working or a memory module installed in this memory slot is not working?

Are both memory modules fully seated, with the locking tabs closed, in the memory slot?

Did your PC ship from HP with one memory module or two memory modules? Try the HP factory memory module or each HP factory memory module, one at a time, in each memory slot to check for a good POST.

Then check memory capacity in Windows Task Manager if the PC will POST using each memory module in each memory slot.

Regards