Hi Feda,
It is easy to do so, just follow these steps:
1) Disable slider from the control panel -> slider
2) Go to io-pro-functions.php file inside the “inc” folder, take backup and remove lines from 127 to line 138.(commented as flexslider and its css)
The above steps will stop loading the slider js and css files in the front end. If you want you can remove these files(slider js and css) permanently from “js” folder after the step 2.