What makes you think that this is a Bitcoin Private key?

Was it written on a piece of paper (or in a text document etc) labelled "Bitcoin Private Key" or something similar (like a paper wallet printout etc)? Or was it just 32 hex characters that you had noted down somewhere? Are there any notes or indications as to what software/system these 32 characters came from?

If you can identify where these 32 hex characters from, you might have a better chance of figuring out how it leads to a private key.