What OS?  We use BitLocker at work and it supports multifactor on the boot drive (assuming you can enable TPM in the BIOS).  I've also heard good things about VeraCrypt which is a fork of the very popular TrueCrypt.

It's very easy and built right in if you were using Ubuntu.  I have never done it with Windows OS.
 
My only advice to you is to be prepared for greatly reduced operating system performance if you encrypt your drives with anything stronger than the weakest encryption algorithms.  Encryption primarily taxes your CPU performance.  Make sure that CPU performance is not already a concern before encrypting your drives.  If CPU performance is at all a concern, do not consider anything stronger than AES encryption unless you ABSOLUTELY need the extra security of stronger encryption.  If you decide not to use AES and instead use a stronger cascading AES-based encryption, file read/write performance can be reduced by more than half and the whole operating system will feel sluggish.

Zuhl3156
I thought about using a thumb drive as a 'key' to make my PC inoperable without it but I worry about what would happen if the thumb drive happened to fail. My USB drives seem to have a very high failure rate and the only reliable ones I stilll use are the Verbatim drives I got from Sam's Club allmost 10 years ago.

LOL, that's pretty funny Zuhl cause I have a very similar issue with usb drives. Ive had 4 or 5 different drives that have failed and the only one that still works at all is a 2gb Sandisk Cruzer that I got as as part of a Christmas present probably 10 years ago, which my mother in law got at a CVS. All the high capacity, high speed drives have died within 2 years or so. I had a 8gb Patriot XT drive that lasted the longest at a little more than 3 years, but in all fairness I did beat the crap outta it. :)

Zuhl3156
Some of my newer USB drives give me 'Disk Controller' or similar Error messages whenever I use them. IDK if I should be nervous about using them for anything important. They still hold data intact and I can Read and Write to them successfully. It's just that annoying Error that bugs me. I get always get them on sale and they always have good reviews. They're honestly not worth shipping back for RMA so I just keep using them.

Yup, I wont bother with RMAing them either. Maybe if it was a huge expensive one, but the largest I had was a 32gb Sandisk which was maybe 40 bux when I bought it so im not too worried about them.

Hi. Dose any of the newer Evga boards have the Tpm hardeware built in available.? Would rather use the hardware, than use a usb. Thank you.