Phone turns into a white screen with hourglass in the middle then shuts off. happens several times a day.

Hi it is because the BlackBerry Pearl 8100 smartphone cannot initialize the BlackBerry Device Software or there is a corrupt operating system file.
To resolve this issue, reload the BlackBerry Device Software on the BlackBerry Pearl 8100 smartphone.
To perform an installation of the BlackBerry Device Software using BlackBerry Desktop Manager version 4.5 to 5.0, perform the following steps:
1) Open BlackBerry Desktop Manager. 2) Connect the BlackBerry smartphone to the computer and open the BlackBerry Desktop Manager. 3) Double-click Application Loader.
4) Click Start under Update Software to start the installation process.
5) Type your BlackBerry smartphone password, if prompted, and click OK.
6) Select Options under Device Software Options.
7) Select the check boxes next to the names of the applications to be loaded, and then click Next.
8) Click OK > Next > Finish.
9) When the process has completed, the message The loading operation was successful will appear.
10) Click Close to return to the BlackBerry Desktop Manager.
I hope this information will be helpful to you.