What should step follow for slow running PC?

pres window button and "R" button on keyboard and write "%temp%"
without quation and press enter and delete all these files and instal a good anti various also
it will increase in speed and if not then reinstall your window with formatting c drive

Uninstall unused programs. (AP) ...
Delete temporary files. ...
Install a solid state drive. ...
Get more hard drive storage. ...
Stop unnecessary start ups. ...
Get more RAM. ...
Run a disk defragment. ...
Run a disk clean-up

Uninstall unused programs.
Free up Memory
Delete temporary files.

Run MalwareBytes scan
Run Ccleaner
Run Defrag

Uninstall unused programs and browser extensions, run a virus and malware scan, defrag computer.

restart the pc 2 to 3 times and then click windows+R and click tree and press enter. Do it 2 to 3 times.

Install and use anti virus Avira. Delete unnecessary things

1. Uninstall unused programs
2. Delete temporary files
3. Install a solid state drive
4. Get more hard drive storage
5. Stop unnecessary start ups
6. Get more RAM
7. Run a disk defragment
8. Run a disk clean-up
9. Vacuum out the dust
10. Buy a new PC

Do the Disc CleanUp Activity.

when virus is over then pc is slow

Just delete all useless data

Delete some applications that are not necessary to free your computer or phone for free smartness

Uninstall unused Application.
Delete temporary files.
Install a licensed antivirus
Get more hard drive storage.
Stop unnecessary start ups.
Get more RAM.
Run a disk defragment. ...
Run a disk clean-up.

Keep your local drive C healthy. Do not fill it more than 60%. Use ccleaner to clean your PC and even you can fragment your disks.

Use good antivirus. A licensed one!

Uninstall unused programs. (AP) ...
Delete temporary files. ...
Install a solid state drive. ...
Get more hard drive storage. ...
Stop unnecessary start ups. ...
Get more RAM. ...
Run a disk defragment. ...
Run a disk clean-up.