These will check for any malware on your laptop. Also, run a scan of your antivirus. That way, you will exclude, or find, malware or virus being responsible.
The other thing worth checking is that your C:\ drive isn't getting full
Another thing you can do is to do a System Restore of when the laptop was running well.
Have you installed anything recently? Maybe that could be causing issues.
Post back with the outcome having done these. Someone with more knowledge/experience will be along later and it will be useful to know the outcome of your scans.