Bumping this old thread. I've been trying to work out why my laptop has slowed down enormously over the last week or so. This morning, it took 20 minutes to boot up, and some pages are really slow to load. I use CCleaner every night before I switch off, and I have Avast running in the background, so I try to keep my comp clear of unnecessary junk.
Trying a bit of analytical thinking - never one of my strong points! - I had noticed that I've been reminded that my Free Trial of Malwarebytes Professional runs out in a few days. I had never signed up for this, and though Malwarebytes has been installed since I got the comp several years ago, I rarely use it as it seems to be very slow.
So using CCleaner, I have uninstalled MWB. And pages now load much faster. So then I did a search and found that there is something in the MWB Professional version that uses a lot of CPU power and RAM, and that many others have disabled it, or certain of its features, at least.
Hoping that I'll find a continued improvement tomorrow.