HP Pavilion dv6 Disabled

HP Pavilion dv6-2135ev running Windows Home Premium OA (64-bit) Service Pack 1

Was installing updates from Windows Update without any apparent problems, but when the machine re-started (as was required) it froze solid at the logon password screen and stubbornly refuses to proceed any further. Power down, try again, same results ad infinitum.

When the correct password is entered all that will be displayed is an HP logo and a message to "Press the ESC key for Startup Menu" ... which process, however, does absolutely nothing. (In other words, access to BIOS settings is disallowed, so switching the boot sequence in order to kick-start the unit from a bootable CD just isn't happening.)

Entering an _incorrect_ password (just out of curiosity) produces the message:

System Disable
[ 60227848 ]

Suggestions on how to remedy this?

BTW, the unit may be "oldish" but has resided quietly in a drawer most of its life. It has likely seen less that 250 hours of actual use. My luck the thing seizes up when it would be hauled along on a short trip. Ugggh!

Thanks in advance