Q: How do i export playlists on new itunes version

You shouldn't have to export/import playlists.  If you replicate the complete iTunes library from old computer to new then all playlists, etc. will be available automatically.  If necessary, consolidate the library on the old machine so that all music, etc. is contained with the iTunes folder (default location C:\Users\username\Music\iTunes) - the structure look like this:

Then copy this entire folder structure to the equivalent location on the new computer.  The key point is to ensure that the iTunes database (the iTunes Library.itl file), which contains all the details of playlists, ratings, playlists, etc.) is copied over and that this has the same relation to the iTunes Media folder on both machines.

Apple's guidelines on How to move your iTunes library to a new computer - Apple Support describes the steps required; turingtest2's user tips on Make a split library portable and Backup your iTunes for Windows library with SyncToy describe the methods that may be necessary to restructure your library before migration and a suitable/recommended method for replicating the library respectively.

Did you copy the iTunes Library.itl file as described?  If so, hold down SHIFT as you start iTunes; when you see this prompt:

click on Choose Library..., navigate to and select the iTunes Library.itl file that you copied over from the old PC.  From your description iTunes may be picking of the database for a new library created on the new machine to which you've added your media.  The other advantage of replicating the complete library, including the database, is that iDevices see this as the same library as was on the old machine, so no issues with content being erased when you try to resync.