iTunes does not (and has never) come pre-installed on Windows computers. If you intend to use iTunes (the programme) again, you will have to download the programme and install it on the new computer. Then add back your music as a separate task.
To download iTunes (the programme) to your computer, go to iTunes - Apple. On that page, you can either download the version from the Microsoft Store (click the Get it from Microsoft button) or scroll down to the very small text that says Looking for other versions? Mac OS> or Windows > and select as required.
Once you have installed the programme, you will need to rebuild your library, either from a backup that you have previously made, or by going back to your original sources:
- if you do have a backup, copy it to the new computer by pasting into the Music/iTunes Media folder
If you do not have a backup:
- for music purchased from the iTunes Store, sign into your Apple account in the newly installed iTunes and go to your account page to find your purchases
- music purchased from Amazon, Bandcamp etc., go to your account with that source and re-download your purchases
- music ripped from CDs; re-rip from the CD
- music from other sources; go back to that source