I have a Dell D620 so TPM 1.2 is no problemI can and have turned on TPMMy machine is a triple boot machine, XP, Vista, LinuxXP was installed first then Vista so the BitLocker prep tool believe the system is already setup for encryptionAttempting to turn on BitLocker gets me the same message every time, "Cannot Encrypt disk"I have the latest Bios from Dell and from what I can tell should have no problems.Anyone have a suggestion on where to turn next? I've checked all the system/app logs with nothing showing me the error. I've turned off TPM and had BitLocker try but still get the same message about rebooting after removing all CDs and DVDs from machine. Looking for a place to turn...

I would guess it has something to do with a) the 'active' status of each of your partitions, and/or b) the boot loader that Vista uses. Normally with multi-boot systems, the primary boot loader in the MBR will load first and then provide pointers to the individual boot loaders for each OS w/in each OS partition (which usually requires that each bootable partition be set to 'active'). Since (I think) BitLocker moves the primary boot loader for Vista from the C: partition to the clear-text 1.5gig partition (usually S, and removes the 'active' bit from C: and moves it to S:, BitLocker is getting confused by your multiple 'active' partitions and 2nd stage boot loaders. That is just a guess though, and I have no idea how to correct it, beyond running only Vista as your OS and the other two as virtual machines with VMware.