Help!!-peeing behavior

I've adopted a cat that has a peeing problem!

She uses her litterbox, but occasionally she'll go on the bed. The bed is the only other place she is going. I'm taking her this afternoon to the vet to check for a UTI or any other health issues. She is fixed, and she is peeing, not spraying.

What can i do to stop this?

The medical check is the first best thing to do. I would insist on a urinalysis. It seems a lot of vets will say they "can't" get a sample...and then just prescribe something based on a guess. I wouldn't do that...getting the urine sample isn't impossible. It's hard enough to pinpoint/eliminate some bladder issues, without the test - you'll be lost and frustrated. With a good diagnosis and the right treatment, there is hope.

I would just do that first.

Other things to consider after that...

Is she declawed? Declawed kitties have L-box issues sometimes.
How many boxes does she have? Covered/uncovered? Good quiet locations?
What kind of litter?
Other pets in the house?
Is she at a good weight? Overweight?

The whole story with this cat is this:
A couple that my husband i know had the cat for 2 years, but when they're away from home for a while she pees on stuff. So i took her to a friend that is home all the time. She peed on her bed the first night and then was good for about a week, and then she peed on it again a day ago. Today my friend saw her get on the bed, so she yelled at her "Cleo, No go to the litterbox" and the cat got off the bed and went to her litterbox.

When we adopted the cat, we got her litterbox as well. It is covered so if everything checks out at the vet. Then I'll try removing the cover.

Cleo is declawed and has one very large litterbox. The apartment is a loft so it is very small area. The living room/bedroom are one room, with an open kitchen/dining area and then a small bathroom.

There is only my friend and Cleo in the apartment. I'm not sure what brand the litter is, maybe tidycat or something similar (it came with her)

She visually looks healthy, not skinny, but not fat either.

It may be behavioral, especially because she is declawed. I would still get her checked out medically, though.

I would try a new litterbox. At the least, do like you said and take the cover off but a new one would be even better. I would try Cat Attract litter in the new box. They have it at Petsmart or other pet stores too. It's worked wonders for a lot of cats who avoid the box for some reason.

Well we're back from the vet. She has a small UTI, so she's on antibiotics for 14 days. However, the vet doesn't think that its the UTI causing the problem since she was doing this with the previous owner.

I went and got a new litterbox and the brand of litter my cats use Swheat Scoop. I also purchased the Pet-Ease Pheromone (similar to Feliway but $15 cheaper at Petco, and if it doesn't work they'll take it back).

My friend no longer wants her so now she's at my house. I have her confined to a small room with the litterbox and bowl of food and water and the Plugin pheromone.