Google & Yahoo searches not working properly

Okay,
I am stumped on how to fix this problem. I have gone through the Read This First and ran everything (with the exception of Combofix) and I still have my problem with Google and Yahoo.

Here is the problem:

I log onto the Internet and have my homepage linked to Google.com. I receive a message - The connection was reset. Even typing in the line www.google.com does not bring it up. So, I go to yahoo.com. When I type it in, I am forwarded to Yahoo, but I noticed that the web address says: http://m.yahoo.com. So, I am thinking that I am getting redirected with Malware. I am also having a similar problem with getting to Facebook. It brings me to a different login page (http://m.facebook.com/?mzw) and has a link that says "access to main site, click here". This brings me to the Facebook login site - address is www.facebook.com/?mzw. I have not been using Facebook since this new link has been up, but I think my son has and I am trying to correct it so he can use the computer again. Other websites don't seem to be impacted. I can go to read news on msnbc.com, etc, but I don't know if there is something collecting our keystrokes on the Internet.

I am not having these same problems on my laptop (in another room) which is using the wireless connection to my cable Internet connection that the problem computer is on (it also uses IE as the browser). So, I presume it is the computer not the connections.

The problem computer is hooked directly to the cable for Internet and using Mozilla Firefox v 3.5.5 as the browser.

Does anyone have an idea on what could be causing this? After running all these cleaning programs, I am still encountering the same problems. I can attach the logs from my cleaning process if necessary. Please help.