Help needed please-Network drops after reboot

Good Morning Peoples: I have a Dell Studio laptop(Windows7) connected to my network thru a router and an ethernet cable--Whenever the laptop is restarted the connection is lost even though the other 2 desktop computers are still active and the connection is fine--same thing when I use a wireless router when I'm in another office--This just started in March--the solutuon is that I have to reboot both the modem and the router and then all is OK but if I reboot my laptop or it is automatically rebooted after any updates--same thing happens----I have checked and updated all the drivers--I am certain the router is fine as both of my other computers have never lost their connection--only this laptop----I have searched other "help' sites and have found others with the same issues and unfortunately no answers--maybe I should just take the laptop in to a technician and have him/her check the network cards etc etc---most frustrating especially because the other two computers on the network have never dropped the connection even when my laptop does-----any suggestions would be much appreciated--Thanking you in advance--RPS