Is this the original factory preinstalled Windows 7 larded with bloatware and duplicate utilities that have better versions built into Windows 7? If so I'd get a perfect Clean Reinstall - Factory OEM Windows 7
or at least Clean Up Factory Bloatware.
Otherwise work through the Troubleshooting Steps for Windows 7
establishing a Clean Boot, checking the logs for repeat errors to resolve, utilizing System Resources to find solutions to problems.
I'd study the Scheduled Tasks in the Scheduler to see if you even want them. Most are not needed and can be disabled. You should have control over what runs on your PC and when it runs, not go on blind faith. A good start is to get the perfect Clean Install and then be the master of it going forward.