Usually when I see issues like this it's the Antivirus, anti-malware, or a combination of the 2 "fighting" each other. One thing you can try is running msconfig, click teh "Startup" tab, and uncheck everyting there. Reboot and see if its better. If it is, re-enable one at a time. If not, click the "Services" tab, check the "Hide all Microsoft Services" box, tehn uncheck all the remaining services, and reboot. Then you can one by one add back until the problem re-occurs.