Vista - sounds

hello everyone...i have this weird problem with my compaq laptop vista home premium sp1...this is the problem sometimes the sound is not playing like if you view videos in youtube, watch movies using media player or vlc and also if i play songs in my windows media player it says file not supported or it cannot be played so what i am doing is restarting my laptop and after restarting it everything will work again and after a while it will act different again...sometimes i notice that if i close my internet explorer songs can be played under windows media player...i just dont know hpw to deal with it...by the way my sound card is IDT HD SOUND...hope you can help me thanks

Hi. Before you do anything ....run Malwarebytes and superAntiSpyware to make sure your pc is not infected..:
Malwarebytes.org
SUPERAntiSpyware.com - Downloads
Assume its OK....
Check and see if there is any update for the sound card from Manufacture and MS Auto update .
Install vista codecs ...:

Free-Codecs.com :: Download Vista Codec Package 5.1.5 : With Vista Codec Package installed, you won't need to install any other codec or filter.

allright thanks for the tips...i will do this right away and ill give you feedback if it worked...thanks...and one more thing..i have also this problem that some of my windows font chaged...for example the run window, my limewire, bittorent, delete window all became bold..it changed the way the window look..all other windows are ok...i tried the dpi settings still no go including the effecrs under windows aero..i will upload the exact image for you to have an idea thanks hope you can help me...