No Desktop, No Taskbar, Virus's. Help?

Hello,
Yesterday I (stupidly) downloaded a file and run the program inside. Since then, I've been having some major problems.

First thing I noticed was that I could not access any anti virus sites (as mine ran out... before I downloaded this file). It would keep saying the websites where down, which was false, as they worked on my other computer. Finally, I managed to download a free version of AVG.

So I went to delete this file I stupidly downloaded, and guess what. It moved. Disappeared! So I deleted the program this was for (was getting a key-gen/serial for a game... wont do that again) and things just kept getting worse. I ended up having to reboot the computer. That was not the best thing to do... Well I rebooted, and every time I logged on, it would freeze up and not let me do anything.

So I did the logical thing. I went into safe mode. From there I scanned my computer with AVG, it moved a lot... and I mean a lot of Trojans and other viruses to the vault, and deleted a few unknown ones. Afterwards, I restarted to go back in to normal mode, thinking it was alright, and I did good. Wrong again...

Logged on to find. Nothing. No desktop, no task bar. Nothing. So I tried safe mode again, and funny enough, even safe mode had no desktop or task bar. Just as empty as normal mode. I've gone back onto normal mode, and currently can access the internet through Ctrl+Alt+Del, but I wanted to go in to my computer and sort things out. So I searched it up on the task manager (going new task, browse, desktop, my computer), and it tells me "C:\Documents and Settings\Tegan\Desktop\My Computer.Ink Application not found"

Is this related? So what I want to know is, what should I do. I've tried my best with the experience I have, but it's not enough. I can't go Ctrl+Alt+Del and new task Explorer.exe because that doesn't work either. I want to get rid of this virus now. So please help! And I hope I have supplied enough information for someone to help me.