The cooling mat will have NO effect on CPU temperature .. that said, they're probably not too high at present.
I wonder if it's something to do with the power supply rating ? .. is it the original power supply ?
Is "Add/Remove Panel items" all that's displayed when you click the "white bar" ? ..it looks like you've created a second lxpanel, if there's an option, right-click the "white bar" and select "Delete This Panel" then confirm OK.