Welcome To SPRC
We don't tend to do much work with laptops on SPCR, namely because there isn't a lot of room to work with. Fans tend to be very
small, and difficult to replace, and there isn't a lot of stuff built for retrofitting. You can underclock the processor, if it isn't already using dynamic underclocking software.
The Dell Inspiron 9200 is supposed to be quite quiet, but a lot of people have complained about the screen resolution being too high.
You might try having a look at ARM systems http://www.armsystems.com/
- they do a number of quiet laptops.