If by inactive you mean your S-Corp has no income or expenses, it is relatively simple to create and file a Form 1120S. If you have prepared your personal returns yourself in the past, and/or are generally comfortable installing and using software, you shouldn't have any problems. The program's interview feature will guide you through the process.
I understand I have to file even with no income I just wanted to know if I can do it by mail easily enough and not E-file. My usual accountant fell through last minute and I am just trying to decide if I should file them myself.
Yes, you can mail them in, but to use TurboTax Business software to prepare them, there is a fee whether you e-file or not. You can also file for an extension and continue researching if you want to do your returns yourself or look for another tax professional in your area.
See Form 7004 if you would like to file for an extension.