Audio and Network Drivers not working.

Hi everyone, realy need your help. I restrted my dell (optiplex 745) after i realised that the sound wasn't working. When it came back on the internet was also not working. It seems that my computer is reading either the audio or the network drives. I have tried going into control panel> system to unistall and then reinstall the drivers but they are still not working? I can't donload the drivers because I only have access to internet at wwork because of this probem. Can anyone help me? (I'm fairly good with computers and so will welcome any technical solutions as well) Thanks!