Suddenly no sound on my dell inspiron 1720, vista, sigmatel

you might need a usb to speaker adapterhttp://www.ebay.com.au/itm/USB-2-0-MIC-Speaker-5-1-Audio-Sound-Card-Adapter-/120645945426?pt=AU_Laptop_Accessories&hash=item1c170f0852

hope this help

You may be able to roll back the driver to the previous one. Depending on which operating system you are using, right click on my computer and click properties. If xp then click on hardware tab and click on device mamager. If vista or 7 click on device manager on the left side of window that pops up. Then click on the "+" next to sound then double click on your device. Click on the driver tab and click on "roll back driver". Follow instructions from there. If you cannot click on that button it means you cannot roll back and may need to do a search or the driver and install it manually.
Hope this helps!

Get it re formatted completely and doing a new partition.

Is it black all the time? From when you start your computer to when you turn it off?

Sounds like the backlight is bad.

Here is a set of links to follow to get the appropriate drivers for XP for the 1525. You also might want to check Dell's site they have a list of drivers available for XP and the components.
http://support.euro.dell.com/support/topics/topic.aspx/emea/shared/support/reinstall/en/reinstall_center?~ck=ln&c=uk&l=en&lnki=0&s=gen


Follow this simple Installation step to downgrade Windows Vista to Windows XP.
a. You have to prepare SATA Driver on your USB Disk. You may get the Dell Inspiron 1525 SATA HERE
b. You have to prepare Dell Inspiron 1525 Wireless Card Driver as well known as Broadcom BCM 4311.
c. For Dell Inspiron 1525 Webcam you have to get Creative Labs Webcam that you may get it in the Windows Update Sites.
d. Get Marvell Yukon 88E8040 PCI-E Fast Ethernet Controller drivers.
e.
Video Card Driver Intel GM965
Dell Application Software Quickset
Ricoh R5C833 Flash Drive controller Driver
Sound Audio Driver Dell Inspiron 1525 SIGMATEL STAC 92XX C-Major HD
Download Intel Chipset
Dell Inspiron 1525 Modem Conexant D330,HDA,MDC,v.92,
Touchpad
Notes: After installing windows XP, you have to prepare windows Downgrade XP patch for Dell Inspiron 1525 before installing Dell Wireless 355 Bluetooth Module and finish Dell Inspiron 1525 driver for Windows XP Installation. Enjoy Xp on your Dell Inspiron 1525 Notebooks.

ah, try the FN key and holding i down then quickly pressing the end key without releasing fn, then release them.
i have an inspiron laptop computer too just an older version so this might not work, if it doesnt go to control panel, sounds,audio and etc. then go to "Adjust System volume" or one of the other ones under "Sound" which are already up when you click onto that

-CG

If sound is not working, usually you have to reinstall drivers.

Here is the link to Dell driver download for this model.

Try downloading again the driver from link below:

Here is the link to Dell driver download for this model.

try downloading and reinstalling new drivers
http://support.dell.com/support/downloads/download.aspx?c=us&cs=19&l=en&s=dhs&releaseid=R171789&SystemID=INSPIRONI6400/E1505&servicetag=&os=WW1&osl=en&deviceid=8907&devlib=0&typecnt=0&vercnt=3&catid=-1&impid=-1&formatcnt=1&libid=3&fileid=235761
if it asks do you want to overwrite say yes. this has worked for me and some friends i have helped out

checklist:
1. sound driver 2. microphone settings in volume control applet 3. tap test (tap the area around the microphone and see if eg Sound Recorder picks it up) 4. external microphone
If you get to step 4 before you get anything then your problem is one of missing or damaged microphone.