Re: A window "PC Speedup" was superimposed in your window. Is this a legimate company? I can not find a review on them.
hello jpculver, this is certainly nothing that is included in firefox or endorsed by mozilla - please always download firefox from the official page at getfirefox.com.
it sounds more like a problem possibly caused by adware/malware on your pc. please go to firefox > addons > extensions & remove any suspicious entries (toolbars, things that you have not installed intentionally, don't know what purpose they serve, etc). also go to the windows control panel / programs and remove all toolbars or potentially unwanted software from there and do a full scan of your system with the security software that you have in place and/or a different tool like the free version of malwarebytes.