I've been thrown off track by this many times in the past, but always assumed that I had remembered something wrongly.
It turns out that I have both linux-image-3.13.0-88-generic and linux-image-4.2.0-38-generic
in my standard installation of Ubuntu 14.04.
What the devil's going on here?
No wonder I have struggled to check my current kernel many times in the past. Are these kernels?
I would usually expect a kernel filename to commence with "vmlinuz". Is that right or wrong?
Here are some more screenshots, of other items that always throw me off course. I don't even know which ones are the same and which aren't.
Edit: I just loaded the pictures one-by-one again, because a couple of the screenshots were missing the first time that I loaded them.
One is a old one and one is a new one. Version 4.4 is the new one, and the latest in the Ubuntu repositories, and version 3.13 is the old one and the one that came with Ubuntu 14.04.
You are not running two kernels at the same time. Grub has located many more than two different kernels installed on your system. This commonly happens when the kernel has been updated. Hold down shift while booting your system to display grub, you will then see the option to log into your system with either kernel. It is good to keep two different ones installed in case you have a bad experience with a kernel upgrade, you can then boot into grub and use the older working kernel to get your system stable again.
You can remove old kernels if you wish. I think you are identifying the two major kernels on your system 3.x.x and 4.x.x versus the many smaller updates in your 3 kernel