whole wordpress not working

[Moderator note: Please don’t add ‘urgent’ in your thread title]

when i go to add a product, every field that i have to fill in information EG title, descriptions, category ect, when i click on them, the page goes dark and and a loading box, then every time i click on somewhere else on the website it does the same thing, i am unable to use wordpress, Could someone please help, thank you