Query on portable hard drive security/encryption

I have a portable 1 TB hard drive that I always carry with me as I constantly give sales presentations and training courses using my clients' onsite computer equipment. I'd like to encrypt the disc and/or secure it with a password in case forget it or get it stolen.

Is there any security product that will allow me to access the encrypted files in the disc without the need to install any product on my client's machine? Ideally, I'd like to have something like TrueCrypt, but this requires administrator's right to install it. In other words, I need a product that I can use without having to install anything - perhaps something like a portable application. Although the information I carry is sensitive and confidential, I can cope without having "industrial strength" security but something good enough to avoid someone snooping through my files.

Any advice or ideas will be really appreciated!

Thank yo so much.

 

Here you go:
http://www.rohos.com/
http://www.axantum.com/AxCrypt/Default.html

Lots more options:
http://www.techsupportalert.com/content/probably-best-free-security-list-world.htm?page=0,18