Windows 7 Icon thumbnail problem & can't change desktop solid color background

Steps to Troubleshoot:​

1. Check System Files:
   • Run the System File Checker tool to scan for and repair corrupted system files.
     Code:

      sfc /scannow

   []Reset Icon Cache:
   • Clear the icon cache to potentially resolve thumbnail display issues.
     Code:

      del /f /q %localappdata%\IconCache.db

   []Check for Malware:
   • Run a full system scan with a reputable antivirus program.
   • Use Windows Defender Offline to scan for deeply embedded malware.
   []Windows Update:
   • Ensure your system is up to date with the latest Windows updates.
   []Registry Cleanup:
   • Use a registry cleaner tool to fix any registry issues that might be causing problems.
   []Nvidia Graphics Driver:
   • Reinstall the Nvidia GeForce 9600 GS driver to ensure it's functioning correctly.
   []Restore to a Previous Point:
   • Consider restoring your system to a previous point before the issues occurred.

     Regarding the .SCR Files:​

   • .SCR Files: These are Screen Saver files, but the appearance of black squares on some folders seems unusual. It's possible that the .SCR files may have triggered some deeper system issues.

     Additional Suggestions for Secure Handling of External Files:​

     • Be cautious when handling files from external sources, especially those with unusual extensions.
     • Scan USB drives before accessing files from them to prevent potential issues.
     If these steps do not resolve the issues, further investigation might be needed to identify the root cause. Let's try these initial steps and see if it helps alleviate the problems you are facing with your Windows 7 system.