My son's Leapster Explorer suddenly has no sound. If you hit the increase sound button, nothing happens. If you hit the decrease button you see the volume bar on the bottom of the page. Do you know how to fix this?

I had same problem, just fixed it by a little hack. The volume up switch is broken.
1. Remove accessory door on bottom. 2. Remove all screws on back. 3. Open back cover.
Looking at the exposed board, there are 2 volume switches (back to back). Directly next the switches are four contacts: the upper 2 are for volume down, the lower 2 are for volume up.
4. Place the battery pack on the board and hold it down. 5. Press the power button to turn on the unit. 6. Use a small wire to jump the volume up contacts multiple times to change the volume to maximum (or desired level). 7. (Optional) Remove the volume buttons and throw away the rubber cushions to prevent the volume from changing. 8. Replace everything back in place.

I followed the instructions to above to open the back (bottom screws/plate, battery pack/rechargeable battery pack, remove screws from back) I then noticed that the small connecting metal directly behind the up volume button had broken where it was soldered. I then took a nail file and pressed the metal extension to the grid (small silver bubble underneath it). I replaced the back (be careful of the spring on the large green top button/there is a sliding bar that popped out on me) and the volume works correctly now. Hope this helps!

My Leapster 2 had the same problem. I used your steps to fix it. The difference was the connection point was around on the front. So I wiggled a flat head screwdriver into the front where the up button is. Worked great.

I had the same issue, but I fixed it by Repairing through LeapsterConnect. Just connect your Leapster and when it is ready hit the Settings on the right up corner. Then choose Repair button; you also can hit Reset, but it will erase everything from your Leapster. For me it worked.

Do not take it apart!

I've not seen posts about this issue but my sons touch screen quit working

Hiya, your child probably spilled something on his leapster, honestly there is no way to fix this but if you would like to try putting it in a tub or rice, if it has any liquid in it that should take it out.
Good Luck I hope this helps :D