If the Premiere Pro Timeline is not working, the first step is to restart the app. Close it by going to the Task Manager and selecting End Task. After reopening the application, check if the issue is resolved. If not, try the following solutions:
1. Try a different video to see if the issue is with the video file.
2. Repair any corrupted video files using a video repair tool.
3. Enable Preview Area in the project window to fix a minor glitch in Adobe Premiere Pro.
4. Reset the UI of the application to resolve any issues caused by personalization.
5. Clear the Adobe Premiere Pro Media Cache to remove any corrupted cache files.
If none of these solutions work, update your graphics drivers or try playing a different video file. If the Timeline is missing, enable it in the Windows menu or double-tap on the sequence in the Project window. With these solutions, you should be able to resolve any issues with Premiere Pro Timeline not working or freezing.