i cannot burn an itunes playlist on to a disc

Try right-click > Burn Playlist to Disc from the playlist name in the sidebar over File > Burn Playlist to Disc. The file menu method seems to have been broken for some time. Might pay to test with some erasable discs first. Note you cannot burn content that is in the cloud or comes via an Apple Music subscription.

tt2

Perhaps these articles will help:

Create CDs and DVDs in iTunes on PC - Apple Support

Intro to burning CDs and DVDs in iTunes on PC - Apple Support

If you have problems burning a disc in iTunes on PC - Apple Support

Be aware that you cannot burn songs you leased with an Apple mMusic subscription. They are DRM copy-protected to only play on Apple-approved devices.

There is usually some tiny raised lettering on the door to the drive that gives you a clue. Or you could check the original specs of the machine. The oldest drives only read CDs. Later came drives that could read and write CDs and/or DVD formats. There are further fine details, but if you've burned a CD before with that drive then you should be able to again.

It is possible Windows needs an updated driver for the drive, or it might be that the current version of iTunes needs reinstalling, or the drive could potentially have failed in some fashion. What version of iTunes did you go back to?

tt2

Reboot your computer. Press the CD eject button as the computer starts up. You might need to reinstall iTunes. I presume you have an optical drive with write capability and had a CD-R or CD-RW disc in the drive.

tt2