Question about risk history

Hello,

I have Norton Antivirus 10.1.6.6000 with most current updates.

My computer is fighting a bug because some Web pages are VERY slow and the processor will start whirring like it's working very hard. There are a number of files in the risk history, some of them with Action of Reboot Required - Reboot Processing, Partial, or Reboot Processing. Have rebooted several times over the last week but action status does not change.

Are these files still active and causing problems?  If so, why can't Norton fix? Can they be deleted?

Thanks for help.