Can´t open playstore apps

hello i have a htc desire and i have a problem.i´m always in safe mod, and i can´t open playstore or other aplications, i just can open the original apps (camera,internet...).i can install but after that it only appears uninstall button.i know that my -volume and my trackball don´t work but how can i fix it?
i have 2.3.7 miui.
pls help me!