Dell Latitude e6420 Will not enter bios

I have a Dell Latitude E6420 that will no longer enter bios or boot option. I have tried every possible solution and no luck. I have unplugged the CMOS battery for an hour, tried ctrl+esc to enter bios recovery no go. I removed the hard drive, reseated the ram and other options too numerous to list. I anyone has an idea or what to do I would appreciate it.