How can I trademark my Computer Game software?

You only place a small TM near your logo. it wouldnt hurt to take a picture of ur trademark next to the date of a newspaper or put trademark in envelope and have snail maled to yourself as certified mail. That way u have proof of when you started using trademark. You cando the same with copywrite by putting the small c inside of a circle at bottom of work and include the current year. The R next to logo simple means registered trademark with the same legal rights I believe as the TM which is unregistered trademark.