Headphones only work when I disable and enable them in control panel

I have a Toshiba laptop and Windows Vista and I have recently had a new hard drive installed. Since then I have had a problem with the headphones.

When I plug in the headphones in they do not work and the sound continues to come out of the speakers.  When I go to Sound on the Control Panel I can see icons for both the speakers and the headphones and it states that they are working.

If I make the headphones the default, the sound will come out of the headphones.  When I subsequently unplug the headphones, the sound does not come out of either the headphones OR the speakers.  The only way to restore the sound to the speakers is the disable and the enable the headphones.  Then the headphones do not work again and so it goes on.

I don't want to have to go through this ritual every time.  I have updated the drivers and this made no difference.

I am sure before the PC had its new hard drive enabled the speakers said Realtek, but now they say high defintion audio device.

Thanks for any help