I assume you have the FastSpring version of the game. If Steam, just go to your Steam library and it will be there readty to install.
Back to FastSpring. If you have your license key from your receipt, you can install the game on the new computer and continue from there. The next couple of steps presume you lost the key.
First try here:
https://qlm1.net/ootpdevelopments/qlmcustomersite/
I've also seen this reposted approach work for people in search of their key:
"Let's ensure you can see hidden files.
Select the Start button, then select Control Panel > Appearance and Personalization. Select Folder Options, then select the View tab. Under Advanced settings, select Show hidden files, folders, and drives, and then select OK. We are doing this because the AppData folder is typically hidden so people don't mess with it by accident.
Then navigate through the file folders to: C:\Users\NAME\AppData\Roaming\Out of the Park Developments\OOTP Baseball 23\config .... and look for the key.cfg file. Obviously in the file folder I pasted "Name" is your name.
Right-click key.cfg and open it with Notepad. The computer won't know what to open it with so follow the prompts to manually select a program to open it with. There, in Notepad, is your key. Copy it. Paste it into a Word document so you have it and save that document. "
So, that's the process to find a lost key that I've seen posted and reposted over the years. Again, that first link I gave will also let you deactivate it from a computer that has gone kaput.