Recently my laptop has become

Question

Recently my laptop has become extremely slow, the internet doesnt work and something called Virus Trigger keeps popping up. I have tried to delete it but it keeps saying access denied and i think it is probably a virus so I asked a friend how to reboot the whole laptop but she didnt know. I ran a scan to find out how many problems i had with my laptop and it found 127 problems. How can I get rid of all the problems without having to download anything?