If you get prompted to enter the BitLocker key or password during boot, it may be because the TPM owner is missing or not configured. This is how you force BitLocker to Set Ownership and make sure you’re using the TPM in the first place:
(1) Enable TPM in the BIOS
Access the BIOS and Enable TPM, and then Activate it (if available).
* Important note: if the BIOS isn’t up-to-date, there is a good chance that TPM will not work at all.
Run the following commands from an admin prompt:
(2) Turn on the TPM
manage-bde -tpm -TurnOn
(3) Takes ownership
manage-bde -tpm -takeownership MakeUpAPassword
(4) Adds protectors to the TPM
manage-bde -protectors -add C: -tpm
(and, manage-bde -on c: -s to enable BitLocker, if it isn’t enabled)
(if you are backing up BitLocker passwords—and you should be—manage-bde -protectors -get c: -type recoverypassword)
Other things (related to BitLocker)
Why are you being prompted for a password?
00 – Machine was shut down incorrectly (holding the power in or lockups)
01 – Some type of bootable device/disc is in the USB/DVD-ROM
02 – BIOS lost TPM ownership information
03 – Hard drive is failing
04 – BIOS settings have been reset, upgraded, or power glitches like brownout/blackouts have affected booting
05 – Hard drive letter, formatting, or configuration has changed in some way (MBR was updated)
06 – The TPM has been cleared or TPM information lost
07 – New recovery info has been generated and TPM needs to be updated
* Now, if everything fails, you could just have a bad BIOS or TPM chip, and you may have to use an external USB drive or unencrypted partition on your hard drive to store the .BEK.
* add BEK to another drive: manage-bde -protectors -add c: -rp -rk DRIVE_LETTER:\
Reference
http://technet.microsoft.com/en-us/library/dn466538.aspx#BKMK_SetOwnership