My computer is running very slowly and crashes frequently, could it be infected with malware?

1. Check for full disk storage.
2. Virus Scan the computer.
3. Update virus definitions.
4. Remove system clutter (old files, programs etc.)
5. Check for memory shortages.
6. Scan for spyware/adware.
7. Check if the OS is updated.
8. Install or check the integrity of your Firewall.