Macbook air A1237 short circuiting

Question

I have just bought a macbook air A1237 the 13 inch screen - it was second hand and had a few problems.
First problem was once turned on it was show the restart screen and that would be a constant loop, managed to fix that problem so it starts and works properly
Second Problem - No battery, it wont hold charge - obvious fix replace the battery - need to do,
Third Problem - No sound, the tricky one.
The laptop had already been taken to a computer repair shop before i purchased the item - the shop is obvoiusly not competent enough to work on computers due to the fact they could not repair the restart problem (which took a non-computer techie less then 30 mins). and half of the screws from the device are missing - one on the case and all except one on the battery.
I searched around on the net for a fix for the audio and found a tutorial that said remove the sound ribbon and place it above the battery, so i did this and it worked, turned the machine off and screwed the case back together and no sound... removed the case and i had sound ?? screwed the case back on whilst turned on i had sound for 2-4 hours before it went off... Still only works when the device has no bottom on,
On anther note when i had the device with no bottom on i leaned over the machine and got a shock on my chin, didnt think anything of this due to the case being open, so screwed it all back together and thought f**k it, its a machine with no sound.
After talking to a friend who loves his apple products he mentioned that the device could be short circuiting, so i checked the electric shock on my chin again and i got one from the device and every now when using it i get one on my arm or hand??
So my question is - What could be causing the short and why is the device working properly apart from sound when short circuiting ??  
Also i have downloaded OS lion - the machine is currently on OS X 10.6.8 and it will not let m upgrade? it starts the upgrade then just crashes ? any ideas?
Ps. Sorry for my spelling.

Answer 1

With the keyboard, if working correctly and marked as such, the "3" should also
have the "#" as an option using the Shift key. There are additional hidden keys
that these same buttons can provide, conditionally, with use of the "fn" function
key; this acts like a super-shift key in certain instances. Some keys on a main
external keyboard are condensed on a portable keyboard, & appear with 'fn'.
To tell what the keyboard can provide in various alternatives, you could find
and activate the Keyboard Viewer from within the System Preferences>
International> Input Menu. With 'visible in menu bar' activated, one can
more readily access it and the ability to tell what keys and shift, opt, etc
combinations, or the fn key, can make appear in documents or elsewhere.
The Keyboard Viewer opens into a small window on the desktop, so keys
that are pressed are highlighted on a tiny screen in there. You can also click
on the tiny keys in there to make them work in a document.
Notice the choices in the Input Menu section, as you can set it so Character
Palette and Keyboard Viewer both appear under the Flag icon in main Menu
bar in the Finder or main desktop. Saves having to open Sys Prefs to see it.
Some of the user interface points of reference change over time or between
versions of OS X. So do some names of things, esp with Mt Lion/Mav. In a
way it's good all older Intel-Macs can't run Mavericks 10.9.2. Less trouble.
Other part sources?
http://www.macrepairs.co.uk/parts/
http://www.applemacparts.co.uk/store/macbook-air-c-8130.html
Anyway, hopefully some of this helps a bit.
Good luck & happy computing!