I know this sounds ridiculous but my cat keeps on farting!
She normally sleeps all day because she is an old cat but now she is awake all day farting.
She blows out bubbles of green substances as she does so.
I am really worried as she not eating now or drinking.
Please give me advice.

A visit to the vet is in order, a cat that isn't drinking will dehydrate very quickly, it sounds as if she's really not well.  Even a qualified vet would refuse to attempt diagnosis over the net, so your cat would be better off at the vets surgery ;)

I agree, go to the vets. But this sounds like my OH lol

Don't like the sound of farting with green bubbles. Vet ASAP I think

Margaret