There are several reasons for a sudden slow down. Assuming this PC was reasonable in the past, it has either been infected with malware - in which case it needs to be scanned with anti-malware software and disinfected or reinstall the OS to clean it.
OR the hard drive is in the process of failing, in which case, it needs to be replaced and the OS reinstalled.
I'm not an HP employee. Did this message answer your question? Please indicate below as an Accepted Solution! Did you find this message useful? Click on the thumbs up to give Kudos! " >.
Be alert for scammers posting fake support phone numbers and/or email addresses on the community. If you think you have received a fake HP Support message, please report it to us by clicking on "Flag Post".