nothing is working..not even hijack this.

My system is infected for sure and nothing has been able to detect the infection.

The reason I believe that my system is infected...
- AT times when I search something on Google and Bing and click on the result, the browser get redirected to a different kind of search site, mugrya.org, with the phrase I searched for in it's search box. At some other times browser gets redirected to ads of shadi.com and other sites (through an intermediate landing page...latest of this latest landing page was..."http://268_utr_2642.tictacsearch.com/redirect.php?aid=1031&cid=268&subid=utr_2642&keyword=air+condition+service&url=aHR0cDovLzMwMi5nb3RpdHNlYXJjaC5jb20veHRyX25ldz9xPWFpcitjb25kaXRpb24rc2VydmljZSZlbmM9V2tqR3F6NmVuOVY3WGZXQVZJQUJ0MjBNY3Z3bmgzUlJFT0dQeWRDYmFBPT0").
- At times I get a message, when I have not turned on my internet connection, saying there is no net connection available at this time and ask for a permission to try again or work offline to see the info saved on my system.

I have tried...
- Microsoft windows live care scan online and it detected 9 infections and removed them...the problem still continues..
- Panda live scan online....problem still same as it was

Things are not working...
I have tried all the best malwares listed on cnet...namely Malwarebytes Anti-Malware, Ad-Aware Anniversary Edition, etc but they all are getting installed properly and not running after that.
Just now after coming to this site and reading a lots of posts...I tried hijack this which got installed in C:\Program Files\Trend Micro\HijackThis but the exe file is not running.

I have scanned my system with avira antivir and wanted to scan it with avg as well but it is not getting installed!

please help.