I just got myself a new antec 900 case and everything worked fine until I plugged in my headphones. No sound came up on the headphone and the speaker. I restarted that pc and I now get the message "No audio output Device is installed" I reinstalled drivers but I get "Device object not present" Then I opened the motherboard and plugged ac97 on F_audio. I only plugged HD audio before but now both is plugged. Booted the computer and I still get the message "No audio output Device is installed". I plugged in the headphones and I heard a quiet sound(I think its a spark) and then I smell a burnt smell coming from the motherboard and I turned quickly unplugged the cpu. I waited for a bit and started up the computer and everything runs fine except the audio. I am now scared to plug in the headphones. I think the onboard sound fried or something. But I don't see any burnt marks on my mobo.
Should I just buy a new soundcard or a new motherboard?
I'm also worried about that burnt smell but other than that everything seems to work fine except the sound.
Since you just got a new case, it makes me wonder if you accidentally shorted something out?
My advice is to get a new audio card but maybe run some benchmarks first to stress your computer a little in case it's on the verge of frying. Maybe one of the 3DMark (futuremark) series in a loop for an hour or more.
The Auzentech X-Fi Forte is a really nice card and was recently on sale several places including Newegg. The Forte even has a special design to isolate and drive headphones.
If you want an easy way to confirm there's no audio you could even try downloading and burning a live ISO (like Ubuntu) then boot from CD. That's better than reinstalling Windows.
The burns smell rarely happens without something frying.
If you get a new audio card you need to turn off any onboard audio in your BIOS (which you should maybe do soon anyhow).