Get into "safe mode" and run "system restore" (start/all programs/accesories/system restore) - follow the instructions) - i've copied "how to get into safe mode" from MS below. If system restore won't / can't run - download and run malware bytes from the filehippo website. (run malware bytes even if sys restore does run !
If your computer has a single operating system installed, press and hold the F8 key as your computer restarts. You need to press F8 before the Windows logo appears. If the Windows logo appears, you'll need to try again by waiting until the Windows logon prompt appears, and then shutting down and restarting your computer.
If your computer has more than one operating system, use the arrow keys to highlight the operating system you want to start in safe mode, and then press F8.
On the Advanced Boot Options screen, use the arrow keys to highlight safe mode with networking, and then press Enter. For more information about options, see Advanced startup options (including safe mode).