Laurie, never have stupid questions... only stupid answers
Wellcome to avast forums...
You're probably using Windows XP (as you schedule a boot time scanning and cannot delete the virus).
Please, stop 'System restore' (Control Panel > System > System Restore and then disable it).
Run a full scanning with avast (archives included).
Send the infected files - if any - to Chest. After we can see which is the virus and what you will have to do... Chest is safe and don't let you 'lose' important files...
After all, enable system restore...
Anyway, can't you delete the file when you run a boot time scanning? This is strange...