Search links directing me to other websites and ads

[taniagisell]

PLEASE HELP! Google search links redirect me to Ads and other websites!

So I just got this computer three months ago, about the second month it began redirecting me from google search links to other ad sites, search sites, and just random sites I did not want, I could not find anything to fix it, I stopped using it, then I took it to get repaired from where I bought they said they did not find anything, I am completely helpless I bought this computer for college which I'm about to start in August 24, but what is it good for if it can't go trough a simple google search, I do not have the money to buy a new one and my warranty has expired, it started out fine, I don't why this is happening.
It is also starting slowly, sometimes it won't even start, and everything takes a while to open.
I use Firefox as my browser, the latest version, I have Mcafee security center, It's a Dell X, I just don't know what to do, I hope I can get help here.
I followed the eight steps, did everything as well as I could cleaned my system twice etc. I am not computer savvy at all so bear with me.
Attachments are attached, please tell me if you need any more information.

 

[rev_olie]

**Reply removed due to a forum issue.

Sorry taniagisell I just had to remove this reply due to an outside issue. Someone will be along later to help you

 

[taniagisell]

Thank you for the help, the Combofix log was completely empty, I don't know if that's normal?
when I try to open it, it says it is being used by another application?
But the Hijackthis report did work.

 

[taniagisell]

just checked Google search links and they are working! I've checked and checked and everything seems to be working fine!
Thank you VERY MUCH, I appreciate your help so much, I will definitely come back here if I ever have any problems again.
I just wanted to know, how this happened exactly? I don't think I've gotten into any websites I really shouldn't and how can I prevent it from happening again?
Should I leave Combo Fix on my computer? am I good to go to install new programs?