iTunes wont run?

Today I updated my version of iTunes to the latest one. It all went swimmingly until I ran the program. THe screen went white and was not responding. I waited a while however it didnt change. I eventually closed it in task manger. This is still an issue though as I still can access iTunes. I am using windows 8, does that effect ianything?

Within the picture i've attached it show a huge white backround filling my screen where iTunes should have been however it never loaded up. Not sure what to do... any suggestions?