Nikon D5100 freezes when I try to record video? What Should I do?

I took it on a beach trip when i went with some friends and did a little filming on the beach. I filmed while at the ocean but I don't recall it getting wet at all. Everytime I ty to record the screen freezes and when I turn it off the screen stays at a display until I take the battery out.

Is your memory card a CLASS 10 card? If not, the card may not be able to keep up with the video rate the camera is trying to send to it.

That can produce the results you are having.

If it is a CLASS 10 card, it may be bad. Try another card, or at least reformat the card in your camera.

When you think it has "frozen" it is probably writing to the card. Taking the battery out during this time may have corrupted the card making the situation worse.
Format the card and try again but be more patient - it may take 2 or 3 minutes.

Also be sure you have a class 10 card of good quality - SanDisk Extreme are my preferred brand. Buy from a reputale company - Ebay is awash with fake SanDisk cards that are just carp.