PLS HELP. LOGIN LOOP after installing Avast Home

i installed avast home edition in my XP sp2, after i reboot, i cant login back to my account, even the administrator account. windows just kicks me back to the login screen… i tried repairing it using the installation disc but the problem still there… i tried safemode and still no luck, cant even access system restore… pls help

Did you send system files to Chest?
Did you run avast at boot time? Which automated settings did you use?

Do you have Windows original CD? Can you boot with it at Restore Console and try to run %systemroot%\system32\restore\rstrui.exe … I’m not sure it will work…
http://searchwincomputing.techtarget.com/tip/0,289483,sid68_gci1167895,00.html