Which linux should i install ? I'll instal linux for first time.
My pc is 4gb ram 1333mhz amd quad core and 1gb ddr3 video card.
You should install the distro YOU like and which suits YOUR computer. Only you will know that. We can't tell you exactly.
In terms of popularity look at Distrowatch "Page Hit Ranking" @ http://distrowatch.com/ ---the table on the right hand side. It's not 100 accurate for the most popular distro but it is possibly the best we have got.
For a link to many Desktop versions look at http://www.livecdlist.com/purpose/desktop
Try a few different distros.
Fans of particular distros will tell you to use that. Use Ubuntu. Use Debian, Use Slackware. In the end it is your decision. Just because somebody else likes a particular distro, which suits their computer, doesn't necessarily means that it will be good for you.
Do not immediately and totally get rid of Windows. You can use both through LiveCDs, LiveUSBs with Persistence, Puppy Linux, Wubi, Dual Boot, Virtualisation. See "The few cases where you should stick to Windows (for now)" - http://www.whylinuxisbetter.net/