Phone and contact factory apps "uninstalled" on my Droid

[jacqulip9]

Last weekend both my phone and contacts icons "changed" and when I tried to use them received the message "Application is not installed on your phone".
I took it to the Verizon store where they tried to do what I gathered was a "hard reset" twice (they needed my Gmail acct. information when they performed this task), called technical assistance for more advice and finally the rep installed "Go Dialer" and "Go Contacts" so I could still use my phone.

Is there anything else I can do to restore the phones functions or is this just a sign that it is at the end of its useful life. It just doesn't "act" the same as it did before last weekend.

Thanks for assistance.