Here is the final solution for your sound related Problems
I thank the internet for this forum and notebookforum for this thread. I recently brought a secondhand Toshiba satellte A75 and the sound always gave me problems. I was so upset. i searched the net for solutions and solutions till i came across this forum. I also had a problem that when ever I would write, the lalphabets would bouce to somewhere else or get deleted on it's own. sometimes I would start the Pc and no sound, I would reinstall the software and get sound for a minute or so.
Reading this thread, i would take battery out, then take the AC power out and then press power button for sometime, I got my sound back after starting up with battery and AC power.Please forgive my english as I speak Hindi language.THe Problem is:
The speakers are not grounded at all and static electricity is giving problems.What you need is:
An PC technician or an External Pair of speakers.Here is what I did:
I opened up my pc, starting from the keyboard, just above and F key, put a knife and open the lid, you might have to lever it from the pause break key and the F1 key also. It just snaps up. Put your screen down and take the plastic cover out.
Over there you will find two screws holding the keyboard, open it and lift the keyboard, you will have to jerk the keyboard a little foward, before lifting it up.
Below the keybord you will see speaker wires from the left and right speakers, take them out.
Yeah thats means disconnect your internal speakers. Now if you have access to an IT technician, you could save all that work and ask the technician to solder a wire from the speaker to any metal part on the laptop case, once you have both the speakers soldered, it acts like grounding.
In this case you do not have to disconnect the speakers, but in case you have external speakers, disconnect the internal speakers-this is a good method.
screw back the keyboard and start your pc, plug in your external speakers. you could also disable your modem in your control panel/system/device manager.This has worked for me and I have sound all the time.Hope it does for you guys also.
Best Of luck.