Troubles replacing my Motherboard, need help :s

BEFORE installing the new mobo, check out this possibility. IF it fixes your problem you won't need the mobo and can return it.

If I read your post right, you are using the mobo's Realtek audio system for output to speakers and headphones, and are NOT trying to get sound from your video card. Now, suddenly, after replacing the video card, there is no sound. Is that right?

IF that is correct, you may NOT have any hardware problem at all. The background is that Windows can use only ONE audio output device at a time, and that is set by you manually in a Windows configuration spot, not by adjusting device drivers. These days it is VERY common for people to want the audio to be fed directly to their monitor on the HDMI cable from their video card, and not by a separate set of cables from the mobo's audio output jacks. That is not your way to do things. But getting audio from a mobo chip through a video card is hard. It is much easier for the video card maker to include their own audio output chip in that card and tell Windows to use that device for output, instead of the mobo's audio chip. Thus it has become common that, when you install a new video card with such a system included on it, the automatic utilities that install the new video card's device drivers also install the drivers for its audio chip, and then change Windows' settings to make that new audio system the default audio output device for you. The result is that there is NO audio coming out of the mobo's audio output jacks on the back of your computer!

You can fix this. Go through Start ... Control Panel ... Sounds and Audio Devices (or some similar path), and click on the Audio tab. There are three boxes; in each you can select the Default device to be used by Windows: Sound Playback, Sound Recording, and MIDI Playback. In each there is a selection window showing the currently-chosen device and a drop-down arrow next to that. Under Sound Playback I bet it shows an audio system named like your video card. Click the drop-down arrow and choose instead the Realtek device on your mobo. If you had to do that, also consider setting the proper Default Sound Recording device to Realtek. When done, exit out of those. Now try your audio output and see if it is coming from the mobo jacks to your speakers, etc.

OK, if you want to go that way, this should work. BEFORE doing this, start from my fourth paragraph below to see if you can get the Realtek system to do the job.

If you are routing through the Monitor, first you will need to Install all the device drivers for your new video card - both video and audio drivers. Check the CD that came with the card for how to do that. Once that's done, use the Windows configuration tool to specify that the Default Sound Output device should be the system on your video card. While there, ensure that the Default Sound Recording device is your Realtek system on the mobo.

With those settings the speaker output will be done by the vid card and sent to the monitor on the HDMI cable. Then you'll have to connect your speakers to the monitor's output jack. MAYBE you will need to make an adjustment on the monitor (using its own controls) to ensure that the audio coming in on the HDMI cable is accepted AND sent out on the audio output jack. For the microphone, connect that to the mobo via the rear mic input jack, then READ BELOW about how to ensure that the Realtek system will recognize a mic plugged into its jack.

BEFORE doing any of that, there's another quirk you should check for. Realtek systems typically include a means of re-assigning the functions of the output jacks, and that system can cause you to lose audio. I'll describe how mine works, in hopes yours is similar.

Start his way. Ensure that Windows is set to use the Realtek mobo system as your Default Audio Playback and Recording devices. Ensure that its drivers are installed with no problems. If you have any doubts about this item, check: is the cable from your mobo's Front Panel Audio header to the Headphone / Microphone jacks on the front panel connected securely? Now, arrange your equipment so you have access to the back panel jacks of your mobo AND to your keyboard and mouse, AND so you can see your monitor screen. Follow this sequence.

1. Disconnect all the speaker and mic plugs from jacks and reboot into Windows.
2. Plug in ONE plug - say, the Front Left / Right speakers into the light green jack on back. WATCH your screen for a little window from Realtek saying that it has detected that something was plugged in. It will suggest what this might be (might be correct) and ask for you to confirm or change. If you ignore this it will go away, BUT then it will NOT send any signal out of that jack. You MUST respond to that window by confirming the function (whether you change it or not). Then it WILL send out that sound signal on that jack. This is how the Realtek system allows you to re-assign functions.
3. Plug in a second thing - say, your microphone into the pink jack. Again, watch for the little window and make sure to reply.
4. Continue on, one device at a time, until you have them all connected where you want.
5. Now try to get sounds out of your system. I often use the Realtek utility icon at bottom right (may be under the name of your mobo maker) where you can configure exactly what speaker system you have, etc. AND runs tests sounds out to verify function. If that gets you sounds from your mobo Realtek system as you want them, you will NOT need to go to the trouble of routing everything through the HDMI cable and you monitor.

IF you have routed through the video card and monitor, then you may still need to follow Step #3 above to ensure that the mic plugged into the mobo's rear pink jack is recognized.

With a new mobo I expect yo will need to do a complete new Install of Windows. Is that your plan? If not, tell us what you do plan.

I can't comment on the possible need of doing a BIOS Update of that mobo before installing your existing CPU. Maybe others can. OR, contact the MSI Tech Support people and ask them if that will be necessary.

As far as sound goes, presumably this mobo's Realtek system will work properly. So, you can set it up as before - use the mobo audio system for sound and plug stuff into its jacks. Use the video card only for video. Use the Windows configuration screens to set the Realtek system as your Default Sound Playback and Recording devices. You may have to follow the procedures I outlined for connecting each speaker set, etc. and telling it which device you plugged in where.