redearslider.com

I got this turtle from my Boss. It was her daughter's turtle. The turtles shell looks in bad shape. Can any tell me what I should do for her? I think she is 2 years old.

can you get a closer pic. of the white spots , and tell us how they feel and if they smell.

the most important thing to do is get her a good setup including a heat and UVB bulb above the basking area. be sure and read over the main site. it'll tell you about how to get a good set up

To be honest, her shell doesn't look that bad.
She's in need of a good shed, but I think she'll be fine.
The best thing you can do for her is to get her set up in a good tank with the appropriate temperatures. UVB lighting is especially important for her since she needs to shed. You can also start giving her a balanced diet which she probably hasn't had from the looks of her shell.
Like daniel said, take a look around the main site for how to set up a tank and look at the nutrition section to make sure her dietary needs are being met.
She's a cute turtle- she's lucky to have been rescued by you!

Here are close up on her. She doesn't smell of rot, that I could smell. Her shell is nice and hard. No soft spots on her shell. Is she a red ear slider?

She's a RES.
The white looks like mineral deposits to me, not shell rot. You can probably gently brush it off with some hibeclense and a Qtip.
The other possibility I can think of is that it's fungal. Usually it's more grey though. You can do a forum search and compare your turtle's shell with others and see which looks more likely to you.

The 3rd pic of her belly is shedding, you can seet he loose pieces. they will fall off on their own when they are ready.

Being mainly in the dents like that I would also agree that it does not seem to be fungus . Most time would get cover a in spots not in line like you have.