No sound through speakers.Jack not being detected.HDMI sound only?

So I've got a problem,I changed my case 2 days ago and everything went great,all working as it should be.Up until an hour ago,when the lid got stuck in one of the little clips so after a quick bang it went in.But then I lost my picture on both monitors.
So I went to investigate,I ended up moving the GPU over to the other 16x slot and it is now fine.
but since then I've lost all sound through either the front or rear jacks,It is saying that the speakers are not connected.I've done all the usual checks,as in default devises,drivers.Everything I can think of I have done.I have tried a new cable,and tested through both of my phones and the speakers work fine.I've also tried a few sets of headphones in both jacks.There is a faint hiss sound when I turn the speakers on,that has just started.
I have managed to get sound through my tv via HDMI,but every time,I go into audio manager and lets say change from soft to hard,I loose the sound again,and have to set the HDMI as default again.this too has just started.
I'm using the on board realtek audio sound card ,on an Asus p8z77-lx motherboard.
Just a quick note when I plug in the jack,there is no beep and the pop up screen does not appear as normal.
To me it is pointing towards a motherboard problem,with the 2 problems happening together.Any help would be great.

Hiyya Paul mate sounds like (no pun intended) that thump dislodged something on the board just carefully move the I/O output block and see if there is any movement, could be something a simple as dry joint but which is going to be hard to find and fix.

If you have some warranty and I know it is a PITA having to reef it all out again but.....

Personally I have the P8Z77-V and I just stuck an Asus Xonar DG card in the thing and there is no comparison really and you get one heck of a control centre. Not expensive I don't know about where you are but out here $35 so both my Ivy and Sandy Bridges have them.

Cheers for the reply mate,I haven't stopped trying since I posted god knows how many hour ago that was.I can't see how that would affect the front io panel too though ? I will give it a go though.A sound card was on my list of essentials any way,but after the £300 on case cooler fans/controller cables,god all the little bits add up quick..I'm skint.I'm going to try and scrape £50 up in the am well a few hours and go from there.

No nor do I Paul but try the other USB ports on the board if they are all out then something very wrong somewhere.

Now at least the card will or should bypass that onboard to back panel function, and my front panel still works from those ports in the pic..

I don't know what you have hooked up for sound but I have a Logitec Z506 (5:1) which again is not expensive and with the Xonar control panel on screen the mixing and effects are just fabulous.

John (ex pat Sussex)

All the other ports are working fine.It is only the 3.5mm jacks,the phones/mic,on the front and all 3 on the rear.I'm using the on board realtek sound card(if you can call it that)I have managed to get the sound through hdmi constantly now,instead of having to set the hdmi as default every time I wanted to use it.
I done as advised,and checked to see if there was any play in the io,connections there's not.I resat the mobo,in case there was a short,but it all looks ok . I've removed and reinstaled the drivers a few times,I even tried the version on the mobo install disk.Problem still there.
Everything is pointing toward the motherboards sound area on the pcb,being the problem.Especially as two seperate problems arose at the same time.

So swapping those ports did nothing ? Well if it is the board then perhaps it may have got some static from somewhere while you were changing the case.

Well if you have no warranty and if it was your fault then I wouldn't be holding my breath the card is probably the best way out of this.

If you are concerned re the phones that Logitec system has a phone jack on the control speaker that I use for quality purposes as the front jack is not that crash hot in my view.

I can't understand why it happened,it was up and running for two days before the gpu / jack problem started ,All from that bang of the lid . I've still got warranty left ,so that's no biggy , I have got some pennies sorted out for an early upgrade of the mobo , like I said it was planned but not yet , but Who doesn't like new toys ? The phones aren't really an issue as my Bheringer MS20's active monitors, have a phone out that I use. I opted for active monitors over a sound card with plans to also in the future . At the moment I'm using the HDMI,and connected the speaker through the phone port on the tv ,not the best option but still better than the tv speakers.
Monday I'm going to order the mobo ,MSI Z77 M Power then the week after the sound card ,I'm not trusting the on board again. Thanks for all the help mate..

Ok mate well go with the warranty if you want to. As for the motherboard I don't know much about MSI's so cannot comment too much but have a look at the Asus P8Z77 series the P8Z77-V I used for my Ivy Bridge build is a very well featured board and it is the base model board.

I've got the P8z77-lx at the moment,but am hearing very good things about the msi . Once i receive the new board I will do the whole warranty thing for my back up rig.