It would be safer to perform a clean install. Converting doesn't always work well. And, that system would need to support UEFI. As a 14-year-old laptop, it may not have UEFI support, and almost certainly won't have Secure Boot.
I have an Dell Latitude E5500 but when I convert it to GPT the bios isn't showing secure boot or UEFI
Latitude E5500 Secure Boot and UEFI