hi guys i have one small network problem . hope u people will give any sol

i have one laptop of GM , which need to connect 2 different network one is of Office lan range is 192.168.0.1 which is connected to laptop by wired network. another network coming from sattelite which is of 10.0.x.x connected to same laptop with external usb network card.
the problem is both network i can access the same time, but some time i cant access eiether office lan or sattelite lan.

whenever this problem comes i used to disable or unplug one network cable. and plug it again . then it will start works.

how can i fix this problem .

any solution
thanks
gani