I would download the Windows 7 iso using the tool I linked to in Post#2. Be sure to select the correct version as what is on the computer, Home or Pro. Use Rufus with the downloaded iso to create a bootable USB flash drive. Boot the flash drive. Click Repair computer as shown in this guide and then command prompt. Type the following commands.
list disk is there an "*" asterisk under the GPT heading for your disk?
list volume post the output.
You can also do Startup Repair. It will take up to three attempts to do a repair. If not then we can try using manual commands.
Is there a legible key on the bottom of the laptop on the COA sticker?
Run Rufus with the USB flash drive attached. Select MBR partition scheme for BIOS and UEFI. Leave all boxes as checked. Where FreeDos is shown in the dropdown box select iso image, click the icon, and browse to the Windows 7 iso file. Press Start. Any data on the flash drive will need to be backed up as the drive will be formatted.