Need help ASAP w/ Trojan

I have two computers hooked together on a home network. I have two separate jobs and I use one computer for each job. One of the computers that I use has apparently been infected with the psw.x-vir trojan, trojan-spy.win32@mx, black door trojan, and networm-i.virus@fp. I was going to try to fix this from the information given on these posts, but now i have a new problem. I walked away for a while to cool off and when I came back my computer seems to be frozen. I'm not sure what to even do at this point. Can someone please help me out here. I can't download anything because I can't even get to my desktop - it's frozen partially on Internet Explorer and the Windows screen where you click your user name to go to the desktop.

 

Well, it was partially on both, like it was trying to switch from the login screen to IE, but wouldn't go all the way. I could see the toolbar and the taskbar on IE but I could also see the login button and the Windows emblem with the blue background, and it just froze like that. Nothing would happen if I hit the home button on IE or if I clicked on my user log in. The computer also was making a steady whirring sound, which I didn't even realize until it stopped. Now the noise has stopped and my background is showing with a log in box that says my computer is in use and has been locked. Now it wants me to log in with my user name and password, but I don't have one set up for this computer. I am using Windows XP. I'll try what you suggested and see if I can get in safe mode.