Multimedia Audio controller error code 28. where&what kind should I DL  

hey guys I'm new to this forum. I have a problem with finding appropriate Audio driver after installing windows7. My multimedia audio controller must have not carried over from windows XP or is incompatible.
I already tried downloading a Realtek audio driver and think i followed directions correctly, however there is still no sound and the error message has not gone away. ergo, no sound. I took some screen caps to help you guys see what I've done so far

PLEASE HELP MY COMPUTER FIND ITS VOICE :P

Another one of the problems I've been having is connecting to my local internet connection. Unfortunately i cannot provide all the info because the connection I'm currently using is very unstable. That will be another issue I shall address next.
The internet refuses to connect to the strongest connection. It does not even show thname.
Im currently using a dell tower 32 bit. Optiplex gx620
Using a dell wireless 1450 dual band (802.11 a/b/g) usb2.0 adapter.
Intel pentium d cpu 3.40GHz

An update on the sound driver though. When I switch and run in xp the sound works and I dint have any problems. Back in win7 however I need a new driver according to the computer (see jpeg above)

Thanks for checking this out :)