Help! No sound from laptop speakers, headphones yes!

Any help is greatly appreciated. I have a sony vaio VGN-NW310f laptop with Windows 7. Up until 2 days ago everything was perfect, but suddenly I am getting no sound from the speakers. If I plug in headphones I get sound, but if I unplug headphones, nothing! Well, the computer acts like the sound is working, but I hear nothing.
Right now speaker properties shows I have "High Definition Audio Device" by Microsoft. I know that I had realtek speakers before, but in my attempt to "fix" my problem, I clicked "roll back driver" and somehow lost the realtek and now have the microsoft speakers. I guess it doesn't really matter which speakers I have as long as they work!
Any idea how to get sound again!?
Thanks

Use the System Restore and restore the PC back to a date when it did work correctly. System Restore can be accessed from Start/Programs/Accessories/System Tools. System Restore will not delete any user data or e-mails. As noted select a restore date that is back when it did work correctly.

Hi! I appreciate the advice...I tried the restore and I have "realtek" speakers again......but I still can't hear any sound! Any other suggestions?
Thanks

There is also the possibility that the contacts for the headphones are stuck. That is a common problem.

If you can open the case you can check the contacts. You can also try wiggling the headphone jack around while plugged in to see if that releases it.

after hours of installing and re installing
i just "tried wiggling the headphone" and its works!!!
so i can sleep now
THANKS NilsE

idop: Thank you sooooo much! I had the same EXACT problem and after trying everything along with formatting and reinstalling twice, I saw your post and thought, "What's the chance that wiggling the headphone would work for me?!?" I tried it and IT WORKED!!!! ha ha ha ha ha :::::happy dance:::: I was just about ready to give up. Thanks for taking the time to post. Thanks to you I can sleep, too! It's 1am. I'm done!!