Hello, and welcome.
I'm sorry to hear your kitty is having a problem with using the litterbox. Typically, this can be caused by an underlying medical problem which is causing her discomfort upon elimination. She could have a urinary or bladder infection, cystitis, interstitial cystitis or another condition. Here is more information about urinary problems in cats:
A product that emits calming pheromones for cats, called Feliway, comes in a plug in diffuser and is used to help alleviate stress/anxiety that can lead to inappropriate elimination problems. It is available in major pet stores and online. Here is more information:
You can get a litter additive called 'Cat Attract' to add to her regular litter; this contains herbal attractants which encourage use of the litterbox.
Also, make sure to remove all rugs, like throw rugs, scatter rugs, bathmats, etc., unless you only have wall to wall carpeting that she's using, so this will cut down on her opportunities and make cleaning easier for you. In relation to cleaning, get an enzyme based cleaner for pet or organic stains/odors and only use that to clean where she has soiled. This will completely remove the scent so she doesn't smell it and go back there, again. Some well recommended ones are Nature's Miracle, Zero Odor, Odor Mute and many others found in your pet supply store or even a store like Walmart or Target.
I'm glad you got a new cat box and new litter (make sure the box is not covered and the litter is unscented). It also may be a good idea to get a second box, so she has a choice; some cats enjoy this and the rule of thumb is one box per cat, plus one. Put the second box in a location away from the first. make sure both boxes are not in high traffic areas and not near noisy appliances.
Place her in the box right after eating and take her front paw and scratch with it, so she knows what she's supposed to do there. If she jumps out, try again, but after 2 times, let her go. Put her back in the box in 15 minutes and repeat the same 'scratching', while speaking to her softly and telling her what she needs to do in there. If she eliminates, praise her a lot and give her a cat-healthy treat, so she associates good things with using the box. I'm assuming that she's urinating around the house, but if she is also defecating, take her stool from the rug/carpet and place it in the box and show it to her, let her smell it, so she knows that where it belongs. Be gentle, don't yell and don't 'push her nose in it', just let her see it, get the scent and then let her jump out of the box.
Your next best step would be to have her evaluated by her vet and ask for a urinalysis and culture to be done, to find out if she has any urinary infections or other problems. If she's also defecating around the house, have a fecal sample tested, too.
I hope this helped and all will be well with your furry girl!
I hope you found this answer helpful and will please take a moment to select a positive rating from the stars at the top of your page, then click 'submit;' this is the only way I will receive credit for assisting you. Thank you very much!
Even after rating, I will always be available if you need additional information; just click 'reply' and I will be glad to continue.