Laptop freezes when running full scan

after renewing my norton subscription my
laptop stopped doing scans and kept saying computor at risk of virus, so I uninstalled and reinstalled norton as advised on this forum after reading the many various posts just tried to do a full scan and laptop has frozen!!! how do I turn my computor off safely when it freezes??? am I wrong in
thinking that norton is a pain in the behind and is more trouble than it’s worth!! there seems to be A LOT of posts with this happening!!