sound now not working

[sash1]

hi guys

firstly i am not good with computers so any advice needs to be put into basic terms lol (sorry)
basically ive had windows 7 on my computer for a few months now, i turned it on the other day and now there is no sound, i have done nothing different and havent installed anything recently, it's worked fine up until the other day. where the sound button is on the toolbar it now has a cross through it like i have it on mute but when i click on it it comes up with this:

The troubleshooter has made some changes to your system. Try attempting the task you were trying to do before.

Problems Found:
Hardware changes might not have been detected Detected (then a hazard warning symbol thing)

can anyone help me??

thanks

 

[fireberd]

First suggestion, use the System Restore and restore the PC back to a date when it worked OK. System Restore can be accessed from Start/Programs/Accessories/System Tools. System Restore will not delete any user data or e-mails but any program updates or installs/uninstalls that were done after the Restore date you select will have to be redone. However, an update may have caused the problem so be careful reinstalling any updates.