Not enough disk space and can't clear temp files?!

Hi,

I am having problems with my acer aspire 5. I have very limited disk space and it says 700+gb are taken by temporary files:

When I try to press on temporary files and clean it, it gives me like barely any files to clear:

I have trawled this forum trying all the commands I can find but they're all making no difference! This is making my laptop unusable, any advice?

TIA