DO NOT post any comments about how stupid or slow hotmail is. I've had this same account for almost 10 years now and I'm not creating a whole new email. If your not going to post anything useful or informative, than do not post at all!
Reload web page(s) and bypass the cache to refresh possibly outdated or corrupted files.
Clear the cache and the cookies from sites that cause problems.
"Clear the Cache":
"Remove Cookies" from sites causing problems:
Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance).
First 2 solutions did nothing, booted firefox in safemode then it worked normally. When I ran it again in "normal mode" it also worked normal again. Not sure why, but whatever, it works now. Thank you for your help
I did follow cor-el's suggestion, clearing all cookies and file history, restarting Firefox, refreshing the screen etc. to no avail.
UPDATE: I found that by disabling the add-on "Mingly", I regained access to a functioning Gmail :-)
Problem solved for me, as I didn't use Mingly anyway.