Bought second hand hp elitedesk

[Annabel686]

Hi I just got this second hand computer today, plugged it in and the first screen says the "memory is different from last setup", so I click esc for setup and nothing happens. I click F1 and it takes me to a screen that says "activation petition not found" And no matter what key you click you can't get out w/o turning the system off. I can't get past these two screens and have been told by a friend that there is no operating system, what do I do? 

[WAWood]

@Annabel686 

Given the date of your post, I would have expected someone to respond to it before this -- but since that has not happened, I will take a shot at it ...

First off, you click F10 to get into BIOS settings.  You may have to press that quickly and repeatedly when you reboot to get to the settings screens.

Second, from your comments, it sounds like whomever had this before you "gutted" it (to use the technical term), removing some of the memory and maybe the hard drive as well.

To check those, reboot it again, pressing F2 repeatedly -- to run diagnostics.  That will tell you how much memory it has and whether or not it still has a hard drive.

Good Luck