Lenovo t400 keyboard keys not functioning properly?

I'm having some kind of issue with lenovo keyboard keys. When i press left arrow key + down arrow key or right arrow key, the keyboard makes a beep sound and the key doesn't work. This happens only when i press them together.one more problem is that when my laptop is in the boot screen of windows the laptop makes a long beep tone.

Might a minor hardware failure. Try cleaning it