Help me please. System is very very slow.

My comp is dead slow. please help me. I have downloaded any thing new recently. Pl help me someone. I cant able to do anything
I dont know if i can donate anything since i dont work.Pl bear with me.

Hello, let's see if you can run HijackThis:

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.