How To Enter Equations Quickly In Class?
If you do choose to invest in a Wacom tablet, Windows 7 comes with a math input panel:
It's not very usable with a mouse, though.
Fast File Encryption for Windows?
I would recommend "KRYPTO", or more precise "KRYPTO 2.0/2006 Professional Multi User Professional Data Fullbit Coding Program". The program uses the best encryption possible (called 256 bit fullbit encryption). Read up on it here:
The application even sports a friendly GUI that is easy to use and allows even novice users to encrypt files.