Computer problems?

My computer said that I was downloading a trojan virus when my system mechanic said that it had an update for me. I didn't think twice about it because there are always updates that pop up for various things on my computer. Then when I tried to download norton for a computer scan, my antivirus said I was downloading yet another trojan. Also when I was on the internet it would change to pages like on ebay that I have never seen before. I can't go to most websites like myspace or send an email. My antivirus is unable to do a full computer scan or any kind of scan so I can't really check to see what the main problem is.What should I do, what can I do? If I reinstall windows, will that help. Really trying to aviod pricey repair shops....Thanks

Computer problems?antivirus software

first off norton is the devil you need to remove it!

it calls many things viruses when its not and ends up corrupting your system, wont go to far in detail about that but i advise you to download this free antivirus app and run it. do not reformat email me if you have further questions!

free

http://www.download.com/AVG-Anti-Virus-F...

Computer problems?computer virus

You have probably contracted some spyware. I would advise to use Spybot Search %26 Destroy which is a free spyware removal software but judging from internet explorer hijacking you might need to use Spyware Doctor which is shareware. You might want to use HijackThis, get a scan log and post it up to http://hjt.networktechs.com/ for checking.