audio not working / windows firewall down?

i recently was working through getting rid of trojans and i believe i might have affected some files that were a part of either my audio or windows firewall. there seem to be no detected sound devices, and on start up, the "found new hardware" thing pops up which i assume is related to the audio device. it searches for drivers and promts me to look for them in windows update but nothing shows up. i've reinstalled my audio driver but it didn't help either. also, i cannot activate windows firewall. i don't know if its always been like this or if it was a result of my recent actions. any advice on either problem would be greatly appreciated.

i ran the directx diagnostic tool and did a direct sound test, got this error: DirectSound test results: Failure at step 3 (DirectSoundCreate): HRESULT = 0x80070057 (Invalid argument(s)) then i messed with the hardware acceleration and it immediately changed to: No sound card was found. If one is expected, you should install a sound driver provided by the hardware manufacturer.