Web pages get hijacked

Sometimes When i use google and click on the page i want get redirected to another site. I have some sort of virus or malware. How do i go about getting rid of it?
To be honest about it i have been running win 7 ult with the firewall on but no antivirus for the last 2 yrs. At least i am being honest about it. Any help would be appreciated. I would like to fix my px and then install avg.

thank you

 

Chaslang, thanks.
I did as you said but the first thing that comes up on TDSskiller is this:

threat detected:
locked file
services.sptd

I dont know what to do about it?
thanks

 

I installed and ran Malwarebytes and it did the trick right away. Showed me a bunch of bad files, including the 2 i knew about but couldnt delete. I checked all the files, none seemed important to me or to my system so i had Malwarebytes delete them all, reboot and all is well.
thanks for your help.

 

If you are not having any other malware problems, it is time to do our final steps:

1. We recommend you keep SUPERAntiSpyware and Malwarebytes Anti-Malware for scanning/removal of malware. Unless you purchase them, they provide no protection. They do not use any significant amount of resources ( except a little disk space ) until you run a scan.
2. If we had you use ComboFix, uninstall ComboFix (This uninstall will only work as written if you installed ComboFix on your Desktop like we requested.)
   • Click START then RUN and enter the below into the run box and then click OK. Note the quotes are required
   • "%userprofile%\Desktop\combofix" /uninstall
     • Notes: The space between the combofix" and the /uninstall, it must be there.
     • This will uninstall ComboFix and also reset hidden files and folders settings back to Windows defaults.
3. Go back to step 6 of the READ ME and renable your Disk Emulation software with Defogger if you had disabled it.
4. Any other miscellaneous tools we may have had you install or download can be uninstalled and deleted.
5. If we had you download any registry patches like fixme.reg or fixWLK.reg (or any others), you can delete these files now.
6. If running Vista, it is time to make sure you have reenabled UAC by double clicking on the C:\MGtools\enableUAC.reg file and allowing it to be added to the registry.
7. Go to add/remove programs and uninstall HijackThis if it present
8. Goto the C:\MGtools folder and find the MGclean.bat file. Double click on this file to run this cleanup program that will remove files and folders
   related to MGtools and some other items from our cleaning procedures.
9. If you are running Win 7, Vista, Windows XP or Windows ME, do the below:
   • Refer to the cleaning procedures pointed to by step 7 of the READ ME
     for your Window version and see the instructions to Disable System Restore which will flush your Restore Points.
   • Then reboot and Enable System Restore to create a new clean Restore Point.
10. After doing the above, you should work through the below link:
    • How to Protect yourself from malware!