DEP is blocking most things?

Sorry if this is the wrong place.

Recently my laptop's been telling me that it needs to close a program
because of DEP.
I went to see if I could edit the DEP settings, and they've been
blocked.
I tried opening the command prompt as administrator and using the
following code:
'bcdedit.exe /set {current} nx AlwaysOn'
Most websites said to do that
But no luck, it's still blocked.

It's blocking:
-iTunes
-Media Player [only with playing video's, music is fine]
-Websites that use alot of movement.
-COM Surrogate
-Windows Explorer [sometimes]
There could be more.

Basically it's really annoying me and I really need itunes at the
moment.
If anyone can help I would be very grateful.

Sorry if I didnt provide enough information, my keyboard is playing up
so it's hard to type alot of stuff.

Thanks.


--
LauraJay