Apologies with my errors with type numbers; I'm a bit dyslexic. The full Model number for the HP 455 is: HP ProBook 455 G1 Notebook PC. Thank you for doing the research on this. I looked under Security section and through all the BIOS and couldn't find secure or fast boot, but I will try again. The RAM in the 6930p is DDR2. Thing is, the installed OS doesn't seem to "see" the HDD. The problem may well be in the BIOS. A very long shot - I'm using USB 3 memsticks in USB 2.0 ports on the HP's, although I successfully installed LL 6.4 on a desktop as stated.
EDIT: On checking the BIOS's for the laptops, only the HP 455G1 had Secure Boot, which was inactive. I think the laptops should run LL, as they run Windows 10.
EDIT: On checking the BIOS's for the laptops, only the HP 455G1 had Secure Boot, which was inactive. I think the laptops should run LL, as they run Windows 10.