How do i go about locating a brother i know absolutely nothing about ?

if you know when and were he was born get copy of birth certivicate,this will have your mum and dads name.and start from there .then you can go up to voters rolls each year ,to find if he is still there.get back to me if you need more information

I used 1800-USSEARCH to find my dad.

All the above is great advice. It helps that he's a male, since that means his last name would not change with marriage. Hopefully you know his last name...or is this an adoption, where the name was changed? I'd post a lot of "looking for so and so" messages in the various places mentioned by the others.

If you have the money, you could hire an investigative service. This is the kind of thing they do pretty well. Also, if you have a photo of him...even as a baby or you know any other information about the time/place of your birth, you might try contacting the local newspaper. My wife found her mother that way...they ran an article with her photo as a very young child...and her grandmother saw it and recognized her.

Good luck!