PC Gets Really Slow At Random On Fresh Install

I have freshly installed Windows 10 onto my SSD and used it fine for about a week. But when I booted it up today it took ages and when it finally booted up everything seemed fine, but after a while everything became slow. For example: launching applications would cause to freeze them, webpages refused to load (yeah the internet became slow too), I couln't open files anymore and it would not shutdown either (I could push the button but it did nothing).

When I restart it (hard reset) after it became slow it took ages to boot again, then I trimmed the ssd, I ran ADW cleaner and scanned for virusses. When I rebooted it booted fast this time like normal (It didn't become slow when doing all those things). I even played some Project Cars but after closing the game and waiting for a bit everything became slow again.