As per the page there are several reasons for this to happen like insufficient power from supply... improper driver installations etc... at the start of article they had mentioned about TDR issue faced in windows Vista and 7.
You can read about TDR in detail here http://msdn.microsoft.com/en-us/windows/hardware/gg487368
After reading the article all i did was
1. open REGEDIT
2. goto HKLM\System\CurrentControlSet\Control\GraphicsDrivers.
3. Add following DWORD "TdrLevel"
4. Set the value to "0"