Something has gone very very wrong

My laptop has started to go very wrong. At first it started with webpages being unable to play sound, everything else was fine. I checked a few blogs and I thought I had the problem fixed, it seemed to go away. Now after another restart I have no sound on IE or firefox and all my media players have stopped playing sound citing missing codecs as the problem. Also my system keeps reverting to the classic windows appearance causing my system to slow down in the process. Restarting only seems to fix the problem for a short amount of time.
please help this one has me stumped.

Wasn't too sure where to post this one. Sorry if i'm misplaced.

 

Hey sorry I just realised where I posted that sorry. I will understand if it's deleted. Please forgive my sins.

 

Can you do a system restore on Laptops?? I havent used one so I'm not sure but try it anyway if you already have not done so

Start/All Programs/Accesrories/SystemTools/System Restore and try and Rollback to a day before the problem started, say if it started on 01/01/2007 then Rollback to 31/12/2006, this may fix the problem 99% of the time it will

 

I've already tried system restore, it has the same effect as restarting it only takes effect for a limited amount of time.

 

Some laptops do have a hidden restore partition which can be accessed by holding a key at boot.May have to check for an online manual for your model.

As for the symptoms you could have a memory leak in one of your running programs.

Open taskmanager and check the mem usage to see if any process is steadily increasing.

Also may I suggest posting a Hijackthis log at the link below.
http://www.theeldergeek.com/forum/index.php?showforum=29