Hi there! I understand you're having trouble opening the old version of House of Fun on your Windows 10 device with WebKit browser. To help you better, could you please tell me:

- Are you running the game through a browser or through an app?
- If through a browser, which browser exactly are you using? (You mentioned WebKit, is it Safari or another?)
- Have you updated the game recently or tried reinstalling it?
- What exactly happens when you try to open the old version? Any error messages or does it just not load?

Meanwhile, I can guide you through some common fixes for this type of issue:

1. Clear your browser cache and cookies: Sometimes old cached data can prevent the game from loading properly. You can do this in your browser settings under Privacy or History.

2. Disable browser extensions: Some extensions can interfere with game scripts and stopping the game from loading fully.

3. Ensure you have the latest version of the game: The old version might no longer be supported, so updating to the latest version of House of Fun can resolve compatibility issues.

4. Restart your computer and try again: This simple step often clears temporary glitches.

If these don't work, depending on your browser and how you access the game, we might need to try advanced steps like checking permissions or reinstalling the app.

Let me know what you have tried so far and what happens when you try to open the game!