I have Alpha Anti-Virus on my computer

my computer is Windows 2000 and yesterday I was on the internet and something came up that said you have a virus on your computer so i clicked it to delete the virus but instead it downloaded this thing called alpha anti-virus and now it blocks every website i go on trying to make me register the virus. different things like fake virus keep popping up ex.(W32.SillyFDC.BAZ-Worm Found) block it. How do I get rid of this virus?

Hello Valthezebra,

Welcome to Geek Police, my name is Origin and I will be helping you today. Please keep the following in mind:

• If you do not get a reply from me or another helper within 2 days, please reply to your topic with the phrase BUMP
  
• If you have any cracked/pirated software in your computer delete them or we will not help you.
  
• Only follow advise from Geek Police Staff and not a regular member.
  
• Do NOT run any tool without Geek Police supervision as it could hinder your system useless.
  

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.