Using the kybd. &mouse that came with the new PC, install them and remove anything else. Remove all other USB device(s). Now, reboot and enter the bios section and verify that USB has been enabled, reset and save if need be then exit out. Hopefully, the PC will work. If not and because this is a new PC, call HP and inquiry or start a trouble call, remember call#, should you need to return. if nothing works, then start the warranty service process, ASAP. Don't drag your feet as time of the warranty service action may refer to the area you need it returned, vendor vs HP.
FYI- I see no reason why the kybd.&mouse didn't work other than improper setting or bad devices.
I am still a newbie, but I thought I was somewhat knowledgable with PC's. I boughtt an HP desktop with an AMD Phenom Quad Core Processor. It has Windows 7(64 Bit) ultimate already installed. I am completely baffled as to why the mouse and keyboard will not work. When the computer is booting up, i can hit f10 and get into the setup menu and the usb microsoft keyboard works perfect when I want to navigate through the menus. However, as soon as windows boots up, and I get to the password page(where the password is disabled), neither the mouse or keyboard will respond, whether I use my wireless keyboard and mouse, or the ps/2 mouse/keyboard. Can anyone please help. I can not figure out what i am doing wrong. I can't hit enter to get past the main windows screen, move the cursor, nothing. In setup mode, it works fine, but no response when windows boots. What am i doing wrong, or not doing? Can someone please help?