Hello, everyone. My laptop's ( dell latitude e6420) spacebar key is not working properly. When I type something it misses sometimes. When I play games online still it creates problems.

Even I tried the spacebar test and it working properly there but when I type msgs or something it does not work properly. 

Anyone can guide me on what can be the possible solution. My friend told me to reinstall the window. But I don't know what to do.