Hi I just installed windows xp on my 1525 laptop, I installed all the drivers that I found on the download page from dell, after I finished I found out that I was missing the following driver
Audio device on high definition audio bus
This is the detail on the properties window
HDAUDIO\FUNC_01&VEN_1095&DEV_1392&SUBSYS_10280242&REV_1000\4&21C1B09&0&0101