Host machine: Windows 7 Home Premium SP1 64-bit
VM: Windows XP Home SP3
VirtualBox v4.3.20
I installed VirtualBox and the virtual machine (Windows XP) December 20, 2014.
Everything worked very well at the time, until a few days ago, and I found the display of a window with an error message and no sound under Windows XP.

I used a snapshot to go back but the problem is still present.
When creating my virtual machine, I have set the sound as follows:
Host Driver: Windows DirectSound
Controller: ICH AC97
What to do to regain its Windows XP?
The sound works fine on the host machine, Windows 7.
I remain at your disposal for any further information.
Thank you.