need help removing Trojan.Zlob-X.a

[cld1122]

My PC became infected with the Trojab.Zlob-X.a virus. Everytime I log onto the internet and everytime I click on a link to go to a new page I get this message: "Critical System Warning! Your system is probably infected with latest version of Trojan.Zlob-X.a. Full system optimization will greatly increase your computers performance and prevent loss. Click OK to download antispyware software(recommended)."

I click cancel and all these other pop-ups appear and it seems like something tries to download. I close everything to stop it. I can see many many other people have the same problem. I followed the steps for cleaning up my PC, which did not help. I attached the HJT log, but I'm not sure what else to attach to help you help me. Please help me get this off my PC! Thank You!