|First go to the mfg's web site and download and install all of the latest drivers for your system.|
Second, uninstall any programs that you never use, most manufactures include a lot of software that they are paid to put there and you have no need for. This is especially true for antivirus software. If there is a trial version on the machine and you install your own preferred antivirus program without uninstalling what they put there, there will be a conflict.
Third, A lot of software is set to start with Windows because they feel that it should be instantly available when (if ever) you need it quickly. The problem with this is that when there are a lot of these programs running all of the time, it actually slows everything down by wasting system resources. If you have programs that you use and do not want to uninstall them but do not use them all of the time as soon as you start Windows, look into their settings and try to set them NOT to start with Windows but only when you want them. If there are any remaining that still start with Windows, run msconfig and go to the Start Tab and uncheck any except your antivirus program and anything marked as Microsoft, Apply and restart the machine.
Fourth, Install and Update Malwarebytes (Free version, uncheck the trial of the paid for version). Check the setting to scan for root kits (place check mark) and run the scan. This program will pick up on many nasties that your antivirus program has missed. It only scans manually when you launch it and is a good tool to run once a week or once a month and when you feel something is not right with your system. Remove anything it finds.
You have to be a little bit crazy to keep you from going insane.