USPS-42dollars for Priority Mail Regular Flat Rate Box (FRB-2) (up to 20 pounds)

13-5/8" x 11-7/8" x 3-3/8 inches. http://www.usps.com/prices/priority-mail-international-prices.htm

I have sent 3-4 bigger shipments (not this flat rate box) with USPS, reaches Kathmandu in 5 days. Last one I sent was around 25lbs for around $135. Flat rate is definitely cheaper for laptop.

Better get a postal service staff you know as the recipient of your shipment (I did that)...don't take a risk by sending it to a general address. You probably know that the staff will take out the laptop and put equal wight of iron or something (based on hearsays...!)