Please mention HP laptops model numbers and BIOS versions?
The latest one is HP 8560P. Bios 68SCF ver F.22 12/22/2011. I'm checking on the the others
We had this problem with random computers as well. It seems to be a combination of the BIOS revision / USB chipset manufacturer & revision and ???
It appears to us that some of the manufacturers tie the keyboard and touchpad as well as other input devices to USB. The PRE-BOOT does not have these drivers loaded before it loads. The only fix we found was to make a new "group" in EPO and have in that group make a new policy assignment - under "boot options" tick "Always enable pre-boot USB Support"
The bad: to fix, you must "emergency boot" with machinename.xml with the WinTech CD (after you have added machine to new group with these options enabled), and sync. The machine will get the new policy and modify PBFS and work after that.
Fixed it for the majority of machines we had with this issue.
We call it "safe-no-boot", its so safe nobody can get into it!
The solution is very simple - change the Boot-Order in BIOS - set the HDD as the last device (or next-to-last, if Boot From Lan is activated on your NIC)
Sounds stupid, but it works