HippieGirl, you say the speakers will not work in either the front headphone or the rear speaker port but the headphones work plugged into the front port? Do the headphones work plugged into the rear speaker port? And the speakers work on another computer. If so it really sounds like a software settings has changed.
If you cant find anything in the settings just plug nothing but you speakers in the right port in the back. Go to device manager, down to your sound device, hit the drop down, find you main sound device, right click on it and click uninstall. Reboot your computer and let windows reinstall it, see if the speakers work. If not then go to Add and Remove and uninstall your sound drivers, reboot and install the drivers fresh.