This is a no name unit, wince, Nav N Go IGO 8.3.4.102680, 4 GB. It worked perfectly until last week, no sure it because of hardware problem or kids played it like a toy pressed buttons entered wrong info.
Now it could be started and load up program and map, but couldn't find the satellites to locate itself. Had tried selecting auto detect in MENU-SETTING-GPS, it shows GPS drivers is successfully connected(Port 1, Baud 38400), but couldn't find satellites till run out of battery.

What else I can do?

Try this:
Connect devide to the computer.
Navigate to the main folder (device\igo). Look for file named sys.txt.
Save copy of the file on the computer, and delete it from device.
Disconnect device from computer and turn it on. Set required basic setings and go out under clear sky to get satellites connection.
Hope it will work.

Thank you.

Had tried to delete the sys file , didn't work.
Opened the sys file, copied the GPS info( Port 1, Baud 4800) to GPS setting, didn't work either .

Try port=1, baud=57600

Perhaps also try deleting or renaming the folder named 'Save' while it's connected to computer, then try it again.
Make a backup of the Save folder somewhere before you delete/rename it, just in case, any of your Pins & user added POI's & any tracks you've saved will be stored in that Save folder.

You could also try looking through the icons displayed once the device has started (before you tap the icon to start iGO8) for one that says GpsInfo, if your device has that it'll show the GPS/satellite information with number of satellites connected & signal strength etc. etc..
This will be independant of iGO8 and is a good indicator whether the device itself is able to get satellite reception, if you get no satellites connected & no signals shown on that screen the device most likely is the problem, if it does display it's getting signals ok then the problem is most likely a setting in your iGO8.

I had kept watching the GPS Status for a while, it occasionally found satellite,one or two. But signal was very weak not stable, could be disappear in next minute. It looks like hardware issue, may be because of improper contact in the unit.

Thanks everybody,

Merry Christmas

Merry Christmas to you too.

As a last resort maybe try resetting everything?
Somewhere on the device there might be a small hole with Reset written near it, normally needs the stylus or a pin to fit in the slot properly, press & hold that in for about 15 seconds.
Also some devices can have a Reset or Factory Settings icon that when tapped will reset the device back to default.
Good luck.

And what happens if you delete the sys.txt post 2
and rename the folder save post 5.
Then select auto detect.

Put it in the open air. IT can take up to half an hour before you get a good signal
(3 satellites or more)