well, the thing just shut down and when it re-start it got a pop up saying the problem name call bluescreen and I did a google search and got something that I dont even know where to started. And anothing happen when I plug in the second external hard drive the tower got hotter the local tech toll me it could be heat build up or the fan is not working. Oh, I forgot to mention the model is HP pavilion slimline s3521p with 4gig of ram hope someone can shed some light to this poor thing