Grab file MD5 quickly

This code will allow you to read a file extremely fast and grab its MD5. On a Pentium D 3.6 ghz it can read Explorer.exe and hash it 50 times in under a second. Please try it out and submit any comments or questions. Update (1/1/08) - Cut down the speed by over 100% by not converting the buffer into a string value. Cut down the size of the code by removing unnecessary functions.