Any issues with a Belkin router? I have actually noticed my mom's laptops having problems with our router.. Her work laptop is an IBM with an Intel wireless card (not sure which model) and she usually gives up and connects with ethernet to avoid those drops. Also, her personal laptop is an HP (not sure which card in that one) but has dropped out once in awhile as well. I have a Belkin PCI card in my carputer, but haven't had any issues with connecting to my router or others. Rebooting the router is a good place to start if you have problems, and channels could be the problem if there is interference. My router has a 'Protected Mode':
NOTE: In most situations, best performance (throughput) is achieved with Protected Mode OFF. If you are operating in an environment with HEAVY 802.11b traffic or interference, best performance may be achieved with Protected Mode ON.
If your router has a similar mode, I would try that. The Sentia could be pumping out radiation in the 2.4GHz range that bleeds out the signal. Also, is this problem happening when on battery, on AC power, or both? I can check my Sentia with a frequency counter to see if it's spewing out interference in this range. Maybe some shielding would do the trick if that's the case..