No Desktop icons/No Start button...HELP!

Hello, I'm hoping you can help me with this.
I'm not sure of the name of the virus so here's a description of what is happening to my PC at home:
I was downloading a file (my mistake) then my computer automatically shut down.
When it booted back up, my wallpaper was displayed but no icons and also there was no toolbar at the bottom that displays the start button. If I right clicked for properties, I get an error indicating "action blocked by administrator".
The windows messenger window does pop up after a few seconds. I can click on the help tab on windows messenger which accessess the internet; however, if I minimize the internet window, it disappears all together.
I tried running my anti-virus software; however, halfway through it, it closes automatically.
I hope that you will be so kind as to assist me with this or if you could direct me on what next step I should take.

Thanks so much.... Jaras

I don't know if this will help but reading other descriptions of problems that sound familiar to mine, it may be called the Vundo Virus..... I'm at work right now but when I get home I'll try pulling up safe mode and running hijackthis for the information I see you guys ask of everyone else, then post the results........

Unfortunately, I'm unable to show the hijackthis information. I'm able to run the program and it starts listing all the information, then disappears. It diesappears so fast, I'm unable to copy the information..... any suggestions? Thanks!

Now when I restart the computer and I keep hitting F8, I can't get into safe mode. If I hit control/alt/delete, it indicates, "Task Manager has been disabled by your administrator".

Also, every so often, a message pops up "thank for cooperation". Any ideas?

Please download the current version of HijackThis from HERE

• Double click and run the installer.
  
• It will install to C:\Program Files\Trend Micro\HijackThis\hijackthis.exe
  
• After installing, you should get the user agreement, press accept and Hijack This will run.
  
• Select Do a system scan and save a log file. This will open a notepad file of everything Hijack This found, copy and paste it back here.
  

I'm unable to open hijackthis. I do show it's listed under C:\Program Files\Trend Micro\HijackThis; however, when I click to open it, nothing happens

Can you rename it? Rename the hijackthis.exe that's in the Hijack This folder.
You can rename it to whatever you want, doesn't matter what it's called.

See what happens, let me know.

Well, changing the name did work and I was able to run the program; however, it disappears quickly and I am unable to copy the readout....

Thanks again for all of your help. At this point, I'm unable to connect to the internet from that computer. I think my next step will be just to re-load windows XP. I know I'll lose all my files and such but at this point, I'm o.k. with that. Thanks again!