My built-in GPS sometimes freezes up or becomes unresponsive. Sometimes it can be difficult to know whether it's really frozen or if it's just taking a while to get a signal lock from all the satellites.
So I'm always using GPS Viewer (http://www.hevis.com.hk/download/GpsViewer1.5.zip)
and when I see no satellites appearing, I simply reset my device, and then I'm back up and running in no time! The satellites appear right away after a quick reset.
GPS Viewer is a must! This FREE utility is really useful.
Here's another tip: sometimes when I open the GPS, it takes a while to lock a signal. But, if I close the GPS, then re-open the GPS, I get a solid blue signal much faster. Not entirely sure why, but it seems to help to toggle the GPS on and off sometimes.
Make sure you set the COM port to COM4. Want a modified version that always starts on COM4? Click here.