My AntiVirus does not start?

i've installed avast antivirus. When i try to open it opens and after a few seconds the entire antivirus application closes. I uninstalled avast and then i installed Kaspersky antivirus. It showed the same problem too.

My AntiVirus does not start?windows

Well, I'm not sure about this - but perhaps you have been infected with a virus that refuses to allow Anti-Virus software to run - I've heard of that happening in the past. Try running an online virus scan, such as TrendMicro's Housecall which can be found here: housecall.trendmicro.com/

My AntiVirus does not start?antivirus download

One thing I think you should do to help yourself is download Microsoft's Malicious Tool Remover. It's a small app and once it's opened and running it'll look for and remove any bad stuff on your system. I would also recommend you getting Spyware Terminator, another free app which will protect your pc in real time. Lastly I'd get CCleaner to daily clean your internet cache so all cookies, especially those nasty MRU's will be done for. It may also help to use a paid subscription antivirus in addition to a free one to further protect you. Hope this helps.
Must be time barred.each year needs fresh

If itis from microsoft Ask help!

( Dont have fire wall ?)
This could be a virus that's switching off your anti-virus.

Start the computer in Safe Mode (Keep tapping F8 as the computer turns on) and run a scan in Safe mode, This will give the anti-virus the chance to kill any virus before it gets a chance to load.
Try this

http://siri.urz.free.fr/Fix/SmitfraudFix...