Inspiron 3800 is a laptop. I don't see anything about an Inspiron 3800 MT, where "MT" typically means "mini-tower". There's a Vostro 3800, but it's a "slim tower", and a Precision M3800 laptop...  
Inspiron 3800 and 3800 MT: what is the difference?
Inspiron 3800 and 3800 MT