Problems with shut down/startup

Not sure if this is the right place for this question. I have a Dell Dimension E521 desktop with Win XP SP2. It has a 2 ghz dual core processor and 3 gb of ram. It will be 3 yrs old in December (of course it's out of warranty). Here's my problem-when I shut down or reboot, I get a window that says something like CSystem Tray Dummy Window and it has a progress bar and an "end now" button. If I let the progress bar go all the way across, it says the program is not responding, etc and my only option is end now or cancel. In order to shut down my system I have to choose end now. Then when it starts up or reboots, my programs aren't all starting up. Specifically my antivirus (which is currently the trial version of Vipre), my wireless adapter (Netgear WG111v3), my mouse properties and probably some other stuff I don't notice. I can start the wireless easily enough and my mouse still seems to be fine even though the properties thing isn't in the system tray. Also the volume thing is not in the system tray anymore. My big concern is my antivirus. When I open it it says it's enabled and all but it never does show in the system tray. I'm using the windows firewall right now after having problems with, and uninstalling, sunbelt firewall.  I'm looking for a new firewall but that shouldn't have anything to do with startup. I checked the startup tab in msconfig and these items that aren't loading ARE all checked and I've unchecked and rechecked them with no results.

Also, and this has been happening for a while, my computer has trouble booting up. When I first turn it on there is a Dell splash screen with a white progress bar at the bottom. That loads halfway and that's it. It doesn't load any further. This happens every time lately. I have to manually turn off the computer and then turn it back on and it boots.

Any ideas? Do you think I need to reformat?? I really really do not want to do that right now. It's the worst time possible-my kids are homeschooled and use the computer for their lessons. They need to get started this week (should have last week but with all the computer problems it's been put off).

thanks :)

Gale