It is possible that you have "over driven" your sound system on your laptop... and it has burned out, but it could be that one or more speakers are damaged.
First thing to do is try the speakers on another computer to see if they work.
But you should also find a person who is a good technician or familiar with repairing laptops to get more advice on what the problem appears to be and what must be done.
First, take a look at the device manager to see if there are red, yellow, or gray flags by some components.
Go to Start->Control Panel->System->Hardware->Device Manager. Click on device manager, then look at all the devices for "flags" that indicate a problem.
Start looking for a computer expert in your area, and check out computer repair stores. Expertise and prices vary widely, but in most parts of the USA, it will cost you at least $20, but sometimes $35 to $65 for a diagnosis. Parts will be extra, if it can be fixed.
Post the Service Tag number from the bottom of the laptop for more in-depth suggestions here.
Thanks x
