hi i have a problem with my inspiron 1520 one is that it keeps shutting down at times and some times i will get a blue screen and others i will not i have changed the memory to 4mb and still gets the same thing i do some 3d designs and some one told me that i can try to configure the graphic card to a Radeon HD4330 but i dont know if the 1520 can upgrade to this so can someone help
Generally speaking if you have changed something, in your case upgrading the memory the chances are any issues you get soon after could very well be linked.
First thing i would check is if its actually compatable with 4gb of memory. Laptops usually are a pain to try and upgrade the graphics, more often than not its not possable. With your machine i would be very doubtful that its possable.