Loss of sound on Inspiron 1525, Vista Home Premium, 4mb memory

I think you inadvertently landed in the Desktop forum; laptop audio is different enough that the forum linked below would be better:

http://en.community.dell.com/forums/3517.aspx

Just to give you a head start before you repost there:  "It suddenly stopped working" is not much to go on; the more details you provide, the better help you'll get.   Start with the Sound Troubleshooter in Vista Help and Support to narrow things down, and it would also help to post any recent changes you've made (updates, new software, etc.).

System Restore to an earlier date may also be worth a try as a "quick fix" if you want to try that:   

Start > All Programs > Accessories > System Tools > System Restore