Change the battery of my gpen 340

Try this - about 2 mins 40 seconds in :

olympus vr 340 part 1

Dis you remove the batteries? Sometimes you have to pull straight up hard to get it to release. Have you watched the video on Youtube about taking it apart? I dont think it will come apart without the batteries removed. That is the only thing I can think of why it will not come apart.

at the command prompt type chkdsk X: /f /r where X is flash drive.If it doesn't work download the recovery tool here http://freeware-fix.blogspot.com/2013/04/usb-drive-is-unreadable.htm

The battery for a Sportline 340 Step and Distance Pedometer are any of the following: AG12, LR1142, SR1142, SR43 or 386 or equivalent.

The battery should last a long time but eventually it will not hold a charge. Here is a very helpful link on how to change the battery if needed.
Thanks for using FixYa
http://www.batteryeducation.com/2010/08/garmin-street-pilot-c340-battery-installation-instructions.html

try to open it on the usb....if not on, it mean that your power integrated circuit are crashed

use the sync option w/ yer Windows Media Player .. i just added 1.56G of music on my element gc-920/940..right click the music file (in WMP) and select "add to sync list"...then click button on the bottom of the list that says"Start Sync"...hope this helps

open your cpu then remove cmos cell for 10 seconds.
alos near cmos u see jumper it is set in 1-2 posirion change it to 2-3 thne power up the computer then again set it to itsd original positionmeaNS 1-2 .

Parallel (IEEE-1284) or infrared. I don't think this model has USB.

Try to change usb port and reinstall driver some port on your PC may not regcognize it.
After I solve it , everything work fine :D