Help me, yahoo has hijacked my computer!!!

My web browser(IE) still usable but there are a bunch of crappy yahoo buttons that Ill never use but the main problem is they HIJACKED MY VOLUME CONTROLS! I have to open yahoo instant messenger and click on the voice conference button if I want to control my volume, as it is now the volume is too low to hear my music and after I go through those steps to get enough sound as soon as I exit the messenger my volume goes back to too low to hear. Cany any experts help me fix this?

If it gives you a Yahoo toolbar, try right-clicking on the toolbar (in a place without buttons) and see if an Uninstall option comes up...

Just removed this from my brother's PC a few days back...

If not, then go to Control Panel, Add/Remove Programs, and find it, then Remove (which will then run Uninstall).