Heya fox01
well the other technical problems you told us should get sorted out first. Without knowing so more details about your "notie" (f.e. operating system, patchlevel of it) I can recommend that to uninstall the sound device driver first and try a reinstall after a reboot. If sound works, I would uninstall the driver for the wireless adapter.
Therefore I've checked over at Dell's website for some support links for your notebook:
Dell Latitude D520How to set up a WLAN connectionI would start with fixing the sound problem:
A collection of all known problems of a Dell Lattitude D520 can be found there:
Dell Latittude D520 support forumDellLattitude D520 Sound problemsThen have a look to fix the wireless problem
Wireless problems -1-Wireless problems -2-Something you should check for also: is there any warranty left?
If you have other questions on this, feel free to ask us here, kay?
Have a great day
B. Udo