|Try uninstalling everything that helps connects you to the internet. That is, network card, router, driver from Add/Remove programs in Control Panel, then re-install them.|
Make sure your Router details are configured right, with the correct passphrase etc.
If you get the internet connection back, try looking for driver updates for the sound card your computer use. You can find out which make is yours by going to, 'Start', 'All Programs', 'Accessories', 'System Tools', 'System Information'.
Click on, 'Sound Device', from the sub-category under, 'Components'.
Information above is all based on if you're running XP but you can do the same for all Windows - the titles will be different that's all.