software issues

Hi, My computer is a Lenovo u530 touch and I got this message that said no hard disk detected and I was playing with the settings and I booted legacy mode I believe. Now I have a black screen that says no bootable device found insert boot disc. My computer doesn't even have a disc drive! WhAt do...

I've been having some issues with various programs after the latest Win 8.1 update. They simply won't start, or run in the background without me getting access to them. I've reinstalled my Chrome browser, and now it works normally, but for some bizarre reason I'm not too keen on reinstalling...