Are you talking about writing a second guitar, recording and mixing in a second guitar? Are you doing both parts.

I dable with guitar pro, but I don't really write, but it is great for mixing. I also use garageband but I have a Mac as well as a pc.

More info would probably help the more experienced give you some pointers/advice.

Good luck and if you get it recorded you should post it so we can hear it.

Jaime