Help! iPhone 4 icons disappearing!

[camel517]

I unlocked my iPhone, and here's what happened:

The calender icon vanished
I put it on sleep and opened it back up, and then it my icons in the folders disappeared.

So I rebooted the phone, and then the sound hound icon vanished.

Every time I change the page of homescreen I'm on, a different app's icon disappears.
Is anyone having this problem? What should I do?

 

[vansouza]

do a hard reboot

 

[angusslo]

Had same problem on iOS 4.1 and iPhone 4, did a hard reboot and it's working now.