Norton Anti-virus questions - Files that will not delete?

Norton Anti-virus does a scan for virus it detects a few -attempts to delete the infected files but fails with about 5 of them. The ones that fail to delete are not deleting becasue they are in use. When I go to find the file in the windows directory directly they will also not let me delete them becasue windows gives and error message that the file is in use.

I have tried Cotrl+ALT+Del and the infected file running can not be stoped by clicking end task.

So How can I make the infected files not in use. Would it work if I tried to run Anit-Virus software outside of windows? Can this be done?

or boot into safe mode or recovery console to delete them