Alienware Aurora R2

Hello, i have an Alienware Aurora R2 that i purchased at late 2010 with
 
 - Intel Core i5 CPU 760 @ 2.8 GHz
 - 2x2GB ram 
 - Nvidia Geforce Gtx 460
 - 525watts

 i have been having issues with the graphic card, im not able to update the graphic drivers to the latest released from Nvidia, because if i do, i would get bluescreen about a month later. i was advised to use the dell's graphic driver provided which they had never ever update, hence now im planning to ugpgrade my graphic card to a Gtx 660 Ti, my problem about upgrading to the 660ti is that would my 525 watts psu be able to support it? and after upgrading i would probably have to use the nvidia's drivers and would that cause a bluescreen like my current situation?
  
And currently im having another problem, sometimes when im playing games, such as Minecraft, my computer would start freezing with my mouse lagging badly by freezing around as i move my mouse around with it disappearing and sometimes the cursor would have a brown shadow that is pixelated and the only thing i could do was navigate to shutdown or restart my computer using my keyboard 
i had experienced this problem with Shogun 2, which i solved by enabling triple buffering for the game under 3d settings but it doesn't work with minecraft

This product is very expensive yet not satisfying with multiple problems :(
very very dissapointing