If you are having problem with your Samsung Galaxy Gio runs in Gingerbread OS that automatically shutdown, freeze and randomly reboot, try one of these:
. Install Green Power free or similar (juice defender, this you need to buy at least Plus version).
. Change your Wifi sleep policy to Never.
Go into Settings>Wireless and networks>Wifi settings
then press the menu button >advanced >wifi sleep policy
This is only a temporary solution until Samsung release for an update to fix such bugs on Samsung Galaxy Gio. If the problem still persist you can then do hard reset through settings> factory reset.
or by button combination in recovery mode. Just back all the data stored in your device first.
Press and hold Volume up+Center+Power Button, then select Wipe Cache/Factory Reset. Then select Reboot System.