Ok, then I was afraid of it, as I mentioned before... you most likely have some corrupt data in the kernel and we can only resolve that with a reset.
As long as you have a Google account synced to your device, your contacts, calendar, etc. will be re-synced to the device after you run the initial setup again as long as you sign in with the same Google/Gmail account.
I do recommend you go to gmail.com on your computer and click on the contacts link, then check all your contact groups to make sure the contacts are synced(if not, ask me about contact backup instructions).
Any apps you have, you can also get back by opening the Market, pressing Menu on the phone and choosing "My Apps".
As far as any data that is stored on the SD Card(images, music, etc.), it will not be erased. Only the phones internal memory is formatted.
To complete a Factory Reset follow these directions:
- Go to your Home Screen
- Press the Menu button
- Choose Settings
- Choose Privacy
- Choose Factory Data Reset