Okay, so I've installed Windows 7 on a friend's laptop, a Lenovo R61, that previously had vista. It has a TPM, which is known because it was enabled and managing bitlocker under vista. I disabled bitlocker to upgrade; I also cleared the TPM, just in case. Now, once 7 is installed, TPM disappears. Poof, gone. Device manager can't see it, and there is no TPM in the list of legacy devices to manually add. There's a "security devices" section, but it's empty. Extracting the tpm driver from vista, and using it with "Have Disk..." works, kind of. I can't take ownership of the TPM from tpm.msc. It tells me to do it from the BIOS, but: a) I didn't need to do this under vista b) There is no option to take ownership in the BIOS So, basically, for some reason, Windows 7's TPM compatability has gone walkabout. The inbuilt driver, despite being physically there (ie tpm.ini and tpm.sys are present), seems to be empty, or non-working. Does anyone know why this is? Is there a way around it?