We have 2 Macbooks, one is from 9-2009 the other 8-2010 (my work laptop). The older one has had a lot of problems holding a wireless signal. All other devices (iPhone, other Macbooks belonging to friends, etc) work well. Ethernet is fine. The fluctuating signal tends to happen on other networks (on a recent vacation). OSx 10.5.8. All other software updates have been installed. We do not have any of the defender / protector malware. I have reset the modem and Airport Extreme a few times. Last night I deleted the preference files and it worked great. I continue to check the signal at the top of the screen and it shows 4/4. However, when using it this morning the signal dropped down to 2/4 and 1/4. For some reason if we click on the airport icon the signal improves. It also helps to sometimes click the airport icon repeatedly. I am currently using the problem computer and it's 4/4 again. Any thoughts or recommendations? I was thinking about taking it into my local Apple specialists as it seems limited to only this one Macbook. However, if I can avoid that it would be beneficial (save $ and gain a better understanding of the problems).