getting a no hashes loaded error in hashcat, windows

Question

I'm a beginner in cryptography and I was deciphering a list of md5 hashes using hashcat 6.2.5, the problems that I faced were:

1. my cmd didn't recognize hashcat64.exe as a command but accepted hashcat.exe as a command
2. my text docs don't visually show the .txt extension but are indeed .txt files when checked with properties or path
3. decoding a list of hashes, I used the -m 0 and -a 0 command but when executed, gave the "token exception length, no hashes loaded" error.

how to resolve this issue?