TPMs can be installed into your computer if it supports that extra extension on your motherboard or other types like a smartcard or USB dongle (Thats Not a USB drive!!), however it is more secure to use a 3rd party encryption program like PGP Desktop (Its the Best and most secure since I cant bypass it) or TrueCrypt.... The United States Export laws have made Bitlocker susceptible to cold-boot bypass techniques thanks to its default low memory protection settings (you can disable this bypass technique via GroupPolicy) Personally I can bypass Bitlocker in less than 2 minutes since most dont check the settings, TrueCrypt and most other 3rd party programs are about the same depending on your setting preferences and desired security level
