ME Freezes upon startup...

Hello.

My problem with ME is a reoccuring one. Sometimes (not all the time), while
starting up, ill get a background colour, then before the start bar loads, it
freezes and just sits there with a blue background (my background color...
changes if i change background colour so nothing significant about blue ..
) and a mouse / hourglass. It will stay like this forever until I restart it,
and occationally it will freeze while running scandisk for the improper
shutdown.

I know it is software related because i used to split my hard drive with
linux's kubuntu (which although nice didnt run what i wanted so i removed
it), and It never froze. So its ive kinda ruled out my computer.

One theory I have heard is that norton antivirus 2005 may cause some
freezing, but id rather not remove my anti-virus just to find out that thats
not it and spend 2 hours redoing everything.

Any ideas as to why my computer is doing this or any confermations to the
Norton thing - along with a good antivirus / firewall to use in place of it ?