Try a different USB port
Try the pendrive on another computer
Restart the computer
Check if the pendrive is physically damaged
Clean the USB connector gently
Open Disk Management
Assign a drive letter
Update or reinstall USB drivers
Run CHKDSK on the pendrive
Format the pendrive
Use a data recovery tool before formatting if files are important
Scan for viruses or malware
Disable USB selective suspend
Check Device Manager for errors
Use Windows Troubleshooter
Test with another pendrive to confirm the port works
Replace the pendrive if it is still not detected