The fact that recovering on a desktop does not seem to work can have several causes:
I do assume that you did not get any error messages when entering the restore phrase.
1. You are using the wrong restore phrase. Even if you are sure you have the right one it is often the case. For example, the recovery sentence from a different coin or from a previous attempt on a different device.
2. You are too impatient and do not wait long enough to complete the synchronization process. With a desktop this can take an hour or two
3. You are working with outdated wallet software. Always download the latest version first.
4. Or it may be that your Gulden were still in a so-called legacy account. This is an account that was created in December 2016 when Gulden switched to a new wallet system. If you have left the Gulden in there all this time and now restored it via the restore phrase you have lost those Gulden that were in the legacy account because legacy accounts do not fall under the protection of the recovery phrase as communicated every time the wallet was started. I hope you still have a backup of the file wallet.dat, then you can still access those Guilders but otherwise no more.
This post is also available in: Dutch