Computer with many problems

Hello,

hello everyone,

my computer was infected by virut virus, i tried everything to remove it, i had no choice but to format and reinstall windows sp2..after doing that the virus had gone, but there are still some problems :

1- my computer doesnt have any sound, i installed many times the driver, followed some steps in the forums to disable, uninstall and then reinstall, nothing worked so far...it used to give constantly failure with realtek high definition audio...

2- my computer goes to all websites except windows update and all microsoft websites...means that i did not manage to enable automatic updates till now...

3- i have net protector 2009, and it is an anti virus and a spyware and it scans the computer everytime it starts

4- i also installed ad aware and did a scan and it found nothing

5- i would add that sometimes when my computer starts, it has no icons, nothing in the screen but the picture on the wall paper, and i have to do to task manager and restart so that it works

6- last thing, before my computer was formatted, and whenever i used to restart, a window used to come , log on to windows using password, and it is still coming even after formatting the computer

pleeeeeaaaase help me i tried everything it did not work i really need help

thanks in advance