I am assuming you re-installed your operating system? A couple Qs. I think we will be able to help better if we have clarity on these.
Do you recall ever creating a backup of your "wallet.dat" file?
Are you still using the same hard drive?
And what did you choose as your data directory when you installed Bitcoin Core last time? Did you keep it as default (%APPDATA%\Bitcoin) or choose a different drive/location. Your "wallet.dat" file can usually be found in that directory.
Assuming you didn't create a backup previously nor can find the old "wallet.dat" in your hard drive then it would be a little tougher. All hope is not lost though, because if you're using the same hard drive then with some luck you might be able to recover the old "wallet.dat" file with a data recovery tool.
Yes I installed Windows 10 overtop of itself but chose the option to keep no files.
I do not recall creating a wallet.dat file, but if it was a default option I would gone along with it.
Yes I am using the same hard-drive.
I don't recall which directory I installed Bitcoin core to but it would have been whatever the default is.
Are there any data recovery tools you recommend?
Unfortunately the only way you have is to use a recovery tool, a similar thing happened to me years ago and saved me the "EaseUS" tool but there are also others around very reliable, i wish you the best of luck in recovery the wallet file.