Zorin OS 15.3 Lite not booting after installation

Your op listed the following specs, including BIOS stated as in Legacy mode:

BIOS: MQ96510J.86A.1715.2007.1202.0001 ATA/IDE Mode Legacy

Motherboard: Intel DPT965LT Socket 775
Processor: Intel Core 2 Quad CPU Q6600 2.40Ghz Intel® EM64T Capable
GPU: NVIDIA GeForce 8600 GTS
RAM: 1x2048GB DDR2 667Mhz Single Channel
Hard Drive: SAMSUNG HD321HJ - 320.0 GB
BIOS: MQ96510J.86A.1715.2007.1202.0001 ATA/IDE Mode Legacy

Yes i just don’t understand why isn’t working anything we’ve tried.

I already repaired grub, re-installed grub in sda1 but still no video or no bootable media – Insert a device and press any key

Did the harddrive previously have Windows 7, 8, or 10 on it?

Yes windows 7 ultimate

EDIT: Once again i introduced the usb with zorin os live and ran “Additional Drivers” and detected this:

I don’t know if this helps with something but Zorin detects my gpu

Are you able to boot into Win7 Ultimate? Starting at Win 7, Microsoft introduced "Fast Boot." Fast boot Locks the drive, preventing from any data being written to the drive. That way, it can boot a drive image quickly.
In order to install another OS, the Windows Fast Boot Must Be Disabled, first.

Wow, ok thanks, i will install windows 7 ultimate again, and disable Fast Boot right? I hope that it works because i really like zorin