Help me please winpc antivirurus

Please please help these win pc things keep popping up and driving me mad rattling on about firewall warning ?? I really dont understand computers so please help me id forever be in your debt. I have an essay to get written and im in trouble if i dont do it : (

Hello,

Please read this:

http://www.geekpolice.net/-t3821.htm

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.