Help! Is there a shortcut at boot time to launch boot scan?

I picked up a virus and now my system is so unstable that I can’t even set the scan at boot-time in order to get the system scanned on reboot, because the system would crush with a bluescreen. Is there a shortcut that would launch the boot scan job while rebooting? If not, what do I do? Are there boot floppy disks?

Just run (Start menu > Run):
C:\Program Files\ALWIL Software\Avast4\sched.exe /A:*

Send files to Chest is safer than directly delete. If system files were found, don’t delete them, they could be necessary to boot.

So there is NO shortcut to activate the scan run at boot time. I think it would be super usefull to have such an implimentation. So if I understood this correctly, it has to be done manually once the system is booted. Unfortunatly the system crushes before any command line might be inserted. Thanks, Martin

Even on Safe Mode (pressing F8 while booting)?