Hi! I understand you're having trouble opening PDF downloads with the PDF Gear app on your Windows 10 device. Let's work through this together to find a solution.

First, can you tell me a bit more about what's happening when you try to open a PDF? For example:
- Does the app launch but the PDF doesn’t load?
- Does nothing happen when you try to open the file?
- Do you get any error messages?
- Are you trying to open PDFs downloaded from the web, email, or another source?

Meanwhile, here's a quick checklist of steps we can try:

1. Update PDF Gear App: Make sure your PDF Gear app is updated to the latest version. Outdated versions can sometimes cause loading problems.

2. Try Opening with Another PDF Reader: Test if the downloaded PDF file opens in another PDF viewer like Adobe Acrobat Reader or even a browser. This can help determine if the file itself is okay.

3. Check the PDF File Itself: Sometimes PDFs that are corrupted or partially downloaded won’t open. Try downloading the PDF again and make sure the download completes fully.

4. Clear Cache or Temporary Files: Although PDF Gear doesn’t store cache like a browser, restarting your computer might help release any locked file handles or temporary glitches.

5. Set PDF Gear as Default PDF Viewer: Go to your Windows Settings > Apps > Default Apps > Set PDF Gear as the default for .pdf files to ensure links and downloads open with it.

If you've already tried some of these or if the problem persists with specific files, let me know. We can then look deeper, including app reinstall or checking Windows permissions.

Does this make sense so far? And please tell me what's happening exactly when you try to open a PDF download.