BleepingComputer.com: Internet search links are getting redirected

I'm having a problem where my internet searches are almost all getting redirected to other websites (some advertising, but sometimes it gets redirected to even google). It's happening on both IE and Firefox. Here's a list of the anti-virus programs and such that I already run on a daily basis:
AVG Anti-Virus Free Edition 2011
Malwarebytes Anti-Malware
Ad Aware
They haven't been able to fix the problem.
I just ran Hitman Pro 3.5 and it's saying my explorer.exe and winlogon.exe files are trojans (located in C:/windows and C:/windows/system32 respectively). Although I understand these files are vital to my operating system running smoothly. Any help in this matter would be greatly appreciated, thank you.

Please follow the instructions in ==>This Guide<==.

Once the proper logs are created, then make a NEW TOPIC and post it ==>HERE<== Please include the link to this topic in your new topic and a description of your computer issues and what you have done to resolve them.

If you can produce at least some of the logs, then please create the new topic and explain what happens when you try to create the log(s) that you couldn't get. If you cannot produce any of the logs, then still post the topic and explain that you followed the Prep. Guide, were unable to create the logs, and describe what happens when you try to create the logs.

Once you have created the new topic, please reply back here with a link to the new topic.