Lost all sounds and web page appearance

One day last week I lost all sounds on my PC. No action sounds, cant play CDs or listen to youtube.
All pages are white with black letters. Never had this before.
What's going on with my PC?

Check the connections on the back of yourt monitor. It has all the symptoms of an rgb/scart lead being loose.

All cables are tight, still the same

Right click on your desktop, click on personalise and then go onto display settings. Make sure everythings fine there.

Display says all in order. Still white page on all sites and no sounds

Got a clean up program and it did not help.

Downloaded new drivers and still same look on all sites and still no sound. Is my sound card bad? How do I diagnose sound card to see if it still works?
I realy need my sound back.

I've got problems when playing dvd's on the pc. It all comes out slurry when they speak. Never used to have that problem. But my monitor is making quiet screeching noises.

This is driving me nuts

Two people tried to download drivers for my sound prob but nothing worked, still no sounds. Looks like I need a new PC.