Files not showing

Hi

I have a mac book pro with Lion

Sometimes the files within a folder doesn't show up
I mean, When I go to finder to open a file, the finder just shows the folder, but I can't see the files inside the folder

For example, right now I can't see the files inside the utilities folder

I have to restart the mac in order to see them

Have you experienced this before???
What's the problem???
please help!!

Thanks!!

Hi,
I've not experienced this before but when weird things start to happen on a Mac it's usually time to verify/repair disk permissions.
You may have to find the Disk Utility via Spotlight.