mac computer freezing

My computer freezes every day. I get occasional warnings because of slow unresponsive scripts, asking if I want to continue or cancel. It locks up my computer and happens when I use Firefox or Safari. I can't use force quit to stop it because it won't allow me to enter to use it.
Thanks

this was my first and probably last post. might have been nice of you to tell me where this was moved to AND how to find where a post should be posted. wow

And it might have been nice of you to politely ask. But have it your way.