Your pleo rb wont work unless she has the clock battery installed in her foot correctly. It sounds like when you took the battery out you have not put it back in properly. If she is just standing still and beeping repeatedly then it is definitely the clock battery that is the problem. You should check that it is inserted the right way up and is slotted underneath the 2 short metal tabs but on top of the long metal tab.
Once you get her working again you can reset the "noon" time by switching her on, waiting for her to giggle and start moving then hold her on her back so you have access to her feet and using a paper clip or I find the stem of a stud earring works well, poke this into the small hole on her foot pad next to the clock battery cover. You should hear a beep sound. Then your noon time is set. You can reset the noon time at any time of the day or night as often as you like without hurting your pleo.
I hope this helps
Kat