There's a software called BAND IN A BOX. It's really good, but it's not free.

You will have to download a cracked version or buy it. The pirate version is pretty easy to find, by the way.
Reaper has a free trial that lets you use it forever (or a really long time anyhow, I've had mine for about 3 months now and it works).

The forum already has a section on recording software you can use, you should go check it out. They have a fair sized list of free and purchased software that's good.
orr you can write your own stuff? i hate reading this stuff, if your a "musician" then BE ONE. not some lazy ass that has to use technology to make your life easier. you sir will not be a great musician like Zepplin and Halen and hundereds of others.

But if it is for recording, then try a studio. it may be expensive (unless you work there or have family or a friend that works in one) but its an amazing experience.
Ima Dude Dressed Like Another Dude Playing As Another Dude
Do you want a piece of software to write music for you, or do you want a program such as Guitar Pro? Be more specific with your threads, and remember to use the correct forum. This particular forum - Songwriting & Lyrics - is for the lyrical side of songwriting. It does not pertain to instrument theory. Musician Talk is better for that.