Help! My computer freezes all the time!?

My computer freezes all the time. I can't open kaspersky too. When I open kaspersky, it does nothing. The icon near the clock doesn't even show. When I open task manager, the kaspersky is listed in the processes. It is a avp.exe process. So I uninstalled kaspersky hoping maybe I could fix the kaspersky problem. I uninstalled kaspersky, restarted the computer and I checked the task manager, in the process, Kaspersky is still in there! avp.exe - kaspersky anti-virus 2009. What the heck was that? And my computer freezes all the time. Almost every 10 seconds it freezes, and I can't connect to the internet until I do an ipconfig/release and renew. And before I do the ipconfig thingy, when I try to sign in on msn, it says that my machine's ip address is invalid. All of this happened just today, are they connected somehow? Is it a virus? Should i reformat my pc? Or is there a faster and easier way to fix my computer? It is vista by the way. Thanks, and help would be really really appreciated. I don't wanna reformat it coz my dad will hate me for sure when he finds out what happened to my laptop.