Pressing Tab for edit mode does not work anymore

Basically what i mean is pressing Tab for edit mode does not work anymore and i have to do it manually. I did change some keys around but, i dont remember changing any function that had tab. Any ideas on why this is happening?

PC Specs (If applicable):
GPU: NVIDIA GeForce GTX 660M
CPU: Intel Core i7 3630QM @ 2.4Ghz, 3.2 with Turbo Boost
RAM: 24 GB
OS: Windows 7 Ultimate
Blender Version: 2.71

Check the key binding in User Preferences -> Input -> 3D View -> Object non-modal -> Set Object Mode. See what key it’s bound to and what mode it sets.

It still says Tab as key. There are other keys for Set object mode though. Ctrl Tab 2 of them actually and V key as set object also maybe thats why? and i just discovered that some objects can go into edit mode when i hit Tab but others wont. New models i add wont work with tab, older ones do.

@ 11:16 pm: I finally got it to work as normal! I forgot to check the mode as it was set to Object. i changed it to Edit, and then back to normal. But its still a mystery on how older objects would still go to edit mode while that mode was under object whilst new ones did not.