How do I bypass Avast's startup scan during Windows XP startup?

My mom’s computer got infected with viruses which I have been trying to remove. I installed Avast, and when it asked me whether I wanted it to run the startup scan I checked Yes.

After the computer restarted Avast found and deleted several viruses which was great, but then it stalled (I assume a virus got the better of it).

Now as soon as Windows XP startup sign comes on it gives me an blue screen with an error because I assume that Avast is trying to run and virus won’t allow it (maybe?) - computer just restarts and repeats the process-

How do I get Windows to come on so I can either run scan manually?

Thank you

[font=Segoe UI]It is possible that avast! quarantined/deleted some necessary file(s) causing Windows to boot improperly. If possible, could you boot into Safe Mode & post the contents of aswboot.txt (you may use the Search function of Windows in Start Menu to find the file)?

You should have asked before deleting a virus because sometimes it can cause trouble to your windows :frowning:
If you have the installation cd you should be able to restore important files deleted if not I think you should bring it to your programmer to reformat it :-\

If you can reach safe mode by hitting F8 Restore the computer by system restore to the earliest restore point & reboot. If xp runs in normal boot startup. Run Malware bytes free antispyware run it and remove what it finds & and then re install avast & update & do a boot time scan afterwards. If this does not work you may need windows xp cd rom for repair of windows.