i realize it's sometimes necessary to keep files of a sensitive nature. you can do this with a file encryption program, and do it safely. a password for you computer is not sufficient, they can be hacked in about 5 minutes, no matter what you do. with a file encryption program you can maintain list and registers with out the possibility of prying eyes seeing them.
Tru-Crypt - is an easy to use file encryption software, free, easy to setup and use. it creates an encrypted partition on your computer, when you mount it it looks like an additional drive and is treated as such.
ok you've secured you private files, you can keep backups safely as well, i suggest a thumb drive with the same file encryption software installed on it. you can use a file synchronization software to keep your file synchronized with the same data. i suggest Always-Sync
Always-Sync - it's , free, easy to setup and use, as well. you simply tell it which folders to synchronize and it analyzes them and updates the oldest with the newest.
Tru-Crypt -
http://www.truecrypt.org/downloads
Always-Sync -
http://allwaysync.com/
keep your sensitive data out of the wrong hands !