Greetings from McAfee.
It is good to have McAfee antivirus program installed for a PC. McAfee automatically detects and removes viruses, trojans and malwares and keeps your device safe and ease to use. It also keeps you safe from suspicious or vulnerable websites.
It's not going to affect your computer performance.
Could you please provide the following details ;
How is your computer connected to internet ?
Do we have any other security software installed in the computer ?
How old is the computer ?
Did we have any malware infections in the past ?
For additional assistance please contact our McAfee support.
McAfee Chat Support