Common problem, very easy to fix, very hard to track down.

can be caused by 2 reasons (and not hundreds, as they say on forums, and therefor offer hundreds of solutions that just get you confused):

1. Programming part: Everyone recommends to update the drivers, but after following their words, the problem still stands. This is how to fix it:

For example: your video card is GTX550TI. Downloading the latest driver for GTX550TI is Never enough. You need to download the driver that Exactly fits your video card: there are 4 criterions - GTX550TI GDDR5 1GB 192BIT

As you see -

• GT
  
• GDDR
  
• GB
  
• BIT
  
  All those details should be written on your the box of your video card, If you threw it in rubbish, may the God help you. If you didn't, there also should be a web page of the company that you brought the video card from on that box, download the driver from THAT web page.
  
  2. If the solution above did NOT help, Here is other thing - eject the operative memories, and the video card from your motherboard, clean them off the dust and insert again. Enjoy your gameplay then.

Most recommended Antivirus software by our group is ESET NOD32 Antivirus,[www.eset.com]

• being constantly updated about new scripts of viruses and therefor promising the greatest defence.
  
  
• allowing a fundamental scan of Boot sector, Operative memory, system and local disks.
  
  Download the trial version, and write to commander about taking the licence keys, Our group members take it for free, they have their privileges :)