plug & Play and shut down problems +

I recently moved and when I hooked everything on my computer up things were not working properly. I had a DSL internet service and my computer remained at my old house longer 2 months longer than I did. I am using a Dimension 4550 with Windows XP SE with upgrades. My HP printer would not work when I hooked everything back up and since it is an older printer I just assumed the problem was with it so bought a new Kodak printer. When I followed the install instructions everything went a long fine until time to plug the printer into the USB port. After several hours with Kodak I discovered I had to look for and install all drivers manually as the plug&play was not working and I got the "new hardware wizard" pop-up instead. I thought perhaps this was fixed and maybe only involved this printer (dumb me). I then got a Verizon broadband internet card and it too is a USB connection. Again, had to look for and install all drivers manually. I am still not having my card "recognized" as connected through the normal software I am use and had to creat a dial up style way of connecting to the internet with the "new connection" wizard and the help of the guys at Verizon. That works great but I need to be able to fix my problems... My computer also started hanging on shutdown and I have to manually shut it off with the power button on the tower. When I found out I had to install all drivers due to plug & play not working I was told that my (hope I remember this right...) driver cache had been corrupted most likely due to a virus or something similar. Hence the reason I have come to seek help here. I have ran AVG, S&D and AdAware and am ready for the next step. If anyone is able to help me I would really appriciate it as I want control of my computer back. I also fear I have SEVERAL things running at startup and am not sure which to stop but thought perhaps one of them may be the culprit for the stall at shutdown. rags