Screen resolution problem

hello sir i have a problem with my o2 mini xda phone.sometime the screen is totaly blank ,and when it is not blank the colour was not good.and i get screen display like negative image and as we see image in picture and video mode,it is also like negative or fluorescent image and if we set that image as a wallpaper then the image colour came back.and the speed of operating my phone is very low from when i got this problem.my email id is www.mitulrock@rediffmail.com plz contact me on this e mail id.
thanks........