How to stop guitar amplifier screeching?

I got a small Amplifier at brandsmart for 50$ and its by peavey.It has a volume knob,treble and Bass,and a vintage/modern button.I like my amp to be really loud,so I switch it on vintage to make it loud,but whenever I turn it up too high it makes a screeching sound.I only have a single humbucker pickup on my Guitar.How do I stop the screeching?

Does anyone know of any good guitar tab websites where you don’t have to download anything?

what are some websites that have easy to read Guitar tabs and chords? Are there any that are identical to actual sheet music?

If you could find a link to the tabs of the song Hey There Delilah by The Plain White Tees, that would be awesome, but I mostly just need a website with tabs.