I'm sorry to hear that you're experiencing issues with your PC. Accidentally deleting a system file like Windows.applicationmodel.dll can indeed cause problems with your computer.
Windows.applicationmodel.dll is a Dynamic Link Library (DLL) file that is related to the Windows Application Model framework. It is responsible for various application-related functions in Windows 10.
Here are a few steps you can try to resolve the issue:
1. Boot into Safe Mode: Start by rebooting your computer and repeatedly pressing the F8 key during startup. This should bring up the Advanced Boot Options menu. From there, select "Safe Mode" and press Enter. Safe Mode loads Windows with minimal drivers and services, which can often help resolve such issues.
2. System File Checker (SFC): Once you are in Safe Mode, open the Command Prompt as an administrator. Type "sfc /scannow" (without quotes) and press Enter. This command will scan your system for missing or corrupted files and attempt to repair them.
3. Restore the DLL File: If the previous step doesn't resolve the issue, you can try restoring the deleted Windows.applicationmodel.dll file from your backup or restore point. To do this, you can use the System Restore feature in Windows. Boot into Safe Mode, open the Start menu, type "System Restore," and select it from the search results. Follow the on-screen instructions to choose a restore point before you deleted the file.
4. Repair or Reinstall Windows: If none of the above steps work, you might need to consider repairing or reinstalling Windows. This process will replace any missing or corrupted system files, including the DLL file you accidentally deleted. To do this, you will need a Windows installation media (such as a USB or DVD). Boot from the installation media, select your language preferences, and choose the "Repair your computer" option instead of installing. From there, select the repair option that best suits your situation.
Remember, before attempting any of these steps, it is important to back up your important files and data, especially if you are considering reinstalling Windows. This will ensure that you don't lose any important information.
If these steps do not solve the problem, it may be best to consult a professional or seek further assistance from a technical support forum. They will be able to provide more personalized help based on your specific situation.