Question Non-stop 100% disk usage on a laptop

Sep 5, 2022
One of my friends' laptop has recently got into a problem, saying it has suddenly slowed down massively and is barely usable.

She gave it to me to try and fix it, and as soon as i boot it up, open task manager to check for any bloatware running in the background, i notice that it's HDD is at 100% usage all the time for no apparent reason, and of course opening any program takes a century while the CPU barely goes over 10% usage ( 8 thread Ryzen with 8gb RAM). Tried all kinds of anti-virus/malware software and found nothing. The hard drive says that its at 100% health (?). Any advice?

I was thinking about replacing the disk with a SSD (and ofc a clean OS reinstall), that should for sure fix it, right?