The Mobile Athlon 4 1600+ is a 35W-part while the 1GHz Mobile Duron has a maximum power dissipation of 25W. Since most Laptops' cooling systems are specifically designed for one type of CPU, i doubt your machine will be able to handle the higher power dissipation of the Athlon 4...but it's not impossible. You should ask Compaq to make sure.
------------------------- The opinions expressed above do not represent those of Advanced Micro Devices or any of their affiliates. <center><font color=red>MODERATOR</center></font> AMD Athlon 64 X2 6000+ 89W :: Asus M2N32SLI Deluxe :: 2x1024MB Muskin XP2-6400 DDR2-800 :: BeQuiet! Darkpower Pro 530W :: 2x WD Raptor 74GB/10k rpm, RAID 0 :: ATI Radeon X1950XTX