Security experts say that if your computer has been infected with malware, you shouldn’t restart it. Instead you should turn off Wi-Fi, power off the computer, and start looking for IT help (via ZDNet).
A recent survey (n=1,180) [PDF] of U.S. adults shows that 30% restarted their computer to deal with malware. But sometimes that can actually help the malware. Bill Siegel, CEO & Co-Founder of Coveware said:
Generally, the [ransomware] executable that actually encrypts your data is designed to crawl through attached, mapped and mounted drives to a given machine.
Sometimes it trips, or is blocked by a permission issue and will stop encrypting. If you reboot the machine, it will start back up and try to finish the job.
This is most apparent in cases of ransomware. Ransomware encrypts your files and then the hacker will tell you that they will decrypt their files for a fee. If you restart your computer the encryption process will just pause, then keep going once your computer is fully powered on.