Bitlocker can encrypt anything on your computer, but only comes as part of the Windows 7 "Business" and/or "Ultimate" editions.
If you're worried about securing your passwords in web-pages, look at "LastPass". It stores all passwords in an easy-to-use interface compatible with Chrome, Firefox, IE, etc. Additionally, without the master-password, nobody can get your passwords. (they are never stored un-encrypted. Not even the LastPass team can recover your passwords if you lose the master password.) The best part is... the program is cloud-centric... one account, use it everywhere.