I will post this in steps according to what i think the issue is off hand, if it doesnt work pm me and i will try to assist further

1) right click on My Computer and select Properties

2) Select the Tab that says HARDWARE

3) Click on Device Manager

4) First Take Notice to see if anything is highlighted yellow with a ? by it If so Skip Step 5 and move to step 6

5) Select the Sound, video and game controllers Option and right click to DELETE the drivers.

6) Right Click on the  Sound, video and game controllers and select the option to Scan for hardware changes (Note these all should now have a ? highlighted yellow and will need to all be reinstalled until the ? goes away for each one)

7) If this doesn't work go to www. driverguide. com  (remove spaces) and sign up for a free account. This require clicking a series of ads because it is a FREE account and not a paid one. Turn the power off on your computer and unplug it from any electrical current. On the back off the tower there should be a finger size screw head you will need to remove. Once you do this there should be a cable coming from your hard drive. This cable has a series of numbers written on it. Write them down

Once you do this connect everything power the computer on and pm me, i will tell you which driver to get from the above mentioned website. HOPE THIS HELPS!!! Pm with any further questions

His Dell more than likely does not have a seperated sound card on it for him to pull mod numbers off of so he will not be able to DLoad anything from driverguide-com

If you still have your original disk it will have all the drivers that you need to reinstall your onboard/intergrated sound card/device

If you no longer have your disk here is a link to dell site where you should be able to DLoad the drivers that you need. The link goes directly to teh 4600's support Dload page

http://support.dell.com/support/downloads/devices.aspx?c=us&cs=19&l=en&s=dhs&SystemID=DIM_P4_4600&os=WW1&osl=EN

On some Dells, Compaq, HP, their will not be a per-say actuall sound card driver to sown load and you migh have to download your mother boards driver which will have all the drivers for the circuits on the board IDE, USB, SOUND< VIDEO etc....

Hope this helps.

but why would the drivers suddenly be causing a problem?

Why you ask.. the area on his C: drive that the drivers are loaded from when he starts his computer up may be courpreted. He may have install a new game, and some games will load custon driver files for Video and sound to suit it needs.

It does not take muck for a driver file to get screwed up. Normally windows will reinstall these files by it self and you as the user will be none the wiser. But this self repair by windows may not happen if your machine is running off a Priotery version of windows Dell, Compaq/HP and many others have these versions of windows that it release with it's computer that only runs on it machines due to the hardware in stall.

Priotery version of windows = hacked up version of Microsoft different Windows that are not complete but just what is need to run what ever machine that it is install on.   If you got a new PC and you only got a restore disk with your computer and not a original copy or Windows, you my friend are running a hacked up version of windows setup just for your PC

Most dell come programmed with a one button format (The newer ones anyway)