Please note that I am new to BitLocker but I was able to set it up on my C drive. After doing this, I breifly searched on the web for ways around BitLocker and came up with two articles, Passware Hard Disk Decryption and This $299 tool is reportedly capable of decrypting BitLocker ... disks in real-time. How can I prevent such attacks like these as ways to bypass BitLocker?
Prevent someone from gaining physical access to your system while it's running.
Seriously, the linked tool works by searching through an image of your system's memory for the key for the encrypted volume and using it to decrypt the encrypted volume. The only way to prevent this is to make sure an attacker can't read the memory of a running (or suspended or hibernated) system. There are a number of ways to get this memory image, ranging from connections via FireWire or PCIe to extracting hibernation images from the disk. Of course, even when the system is off, you're not completely safe, thanks to cold boot attacks.