Dell XPS 13 problems with log in, files, and apps.

Hello,

I am using a Dell XPS 13 with windows 8.1. Somehow whenever I try to log in, it takes about 5-8 MINUTES before it would finally be able to go to the start menu. And if this happens, the start button does not work, my files would no longer function and would sometimes disappear but reappear again, then it takes about 10 minutes for me to open any app that I have. Any idea what I could do???