If you see “(32-bit)” and you are running firefox 560 or older, updating to the latest firefox version should automatically upgrade you to 64-bit if you see “(32-bit)” and are running firefox 5601 or newer, then your computer may not meet the minimum memory requirement for 64-bit (3 gb ram or more). Download mozilla firefox 64 bits em portugues. Baixe o mozilla firefox, um navegador web gratuito o firefox