WINDOWS MEDIA PLAYER SKIPS A BIT

I have purchased an HP LAPTOP(i7 5th gen,8 GB RAM,1 TB, NVIDIA 940M 2GB,WINDOWS 8.1).
When I try to play even 480p videos in WINDOWS MEDIA PLAYER,
the player skips a bit few times.
Initially I thought that the file was bad,but when I rewind to the same position, it doesn't skip or get stuck.
I have even encountered this problem in power DVD.
I then went for windows reset(thought windows was infected by virus),cleaned the pen drive in linux installed on another pc,but then also the problem continues.This is happening for most of the files, doesn't matter whether copied from PEN DRIVE OR LAN CABLE.