well i found out what the problem is. it turned out that a worm was interferring with the installtion of avast
. the worm prevented avast installation from properlly finishing and then restarted my computer (tricking me into thinking that avast had restarted my computer), so thats why avast never autostarted upon login.
Avast needs to do something about this so that future users don't come across the same problem that i had.
I would suggest a feature: before the installation actually begins, there should be a check box which says the following "Randomize the installed file name of avast (check this box if you think you are infected, if you are unsure if you are infected or not check this box anyway)". Now i'm no malware expert but i'm presuming that the worm would not have been able to mess up the avast installation if there was such a feature.
note:prevx has such a feature