Yes, you can stile file 2016 without having filed for 2015.  However, the IRS will likely require you to file 2015 before they pay your 2016 refund, especially if they think you could owe money.  So, you should still prepare your 2015 as soon as you can.  Below is a link to past year's TurboTax programs that you can use for 2015 -

https://turbotax.intuit.com/personal-taxes/past-years-products/