help with vaio E series (first i3 gen)

hello, i have an issue with this laptop, it does not load the SO, sometimes it boots up and gets stuck on "starting windows" or it shows "SO not found".
i've tried with the recovery partition but i can't get to repair the SO because it says something like there's a device connected.
as last resource, I'm thinking on make a clean install but I'm not sure how I will get to activate the windows with the license on the COA.
any help will be appreciated

srry for bad english

 

1. We call it OS (operating system) (took me a few seconds to figure out what you were talking about).
2. Can you tell us the exact error message? If it is a different language, please give both the original and the translation.
3. Did you mess with the BIOS settings? Especially AHCI/RAID settings? If so, go back to the settings you had earlier (just loading BIOS defaults will not cut it).
4. Have you tried a complete system recovery of your C drive? That should do what the clean install will do as far as this issue is concerned.
5. You need to phone Microsoft and get the license activated from the COA sticker on the bottom. Also, there are several utilities that will backup and restore your license after reinstalling, e.g. Advanced Tokens Manager. Josh Cell Softwares: Advanced Tokens Manager - The Activation Backup Solution

 

i realized about SO and OS too , forgot to write it in the correct order (in spanish SO is Sistema Operativo). Well, laptop doesn't get to load to windows desktop, is stuck on the black loading screen with the windows logo, or sometimes after loading the bios it shows the message "operative system not found" (no spanish message), however i haven't touch anything in the bios setup yet.
I can't do a complete restore, i haven't seen any option like that so far, only the option to find errors with the boot up files and repair those, but it doesn't work either