1. System Settings
System settings configured for the deleted user may not be removed, causing conflicts.
2. Viruses or Malware
If the slowdown is caused by a virus or malware, deleting the user will not solve the problem.
3. Solution
To resolve the slowdown, it is recommended to:
Clean up temporary files and unnecessary registry entries
Uninstall unnecessary programs
Check background services
Defragment the disk
Check for and install system updates
Perform a full antivirus scan