start by going to msconfig (start\run\type "msconfig") and have a look in the "startup" tab - try and identify all startup programs - any that you are not sure of uncheck and reboot. If this solves the problem it is one of these files.
Get back to me if this doesn't help
When I boot the above appears "windows system 32 / cmd.exe" as a black box and in the box it shows "installing....." I have no idea what this is and why it's happening. I also find that everything is moving slowly. When I click on something it takes forever for it to appear.
I have McAfee Virus, I have installed SP2, I have SBC Global Browser, and I also installed Adaware and Spyware Blaster as I had so many pop-ups.