Once when watching a movie via Netflix and the second time when playing World of Warcraft my very newly built computer suddenly got super ridiculously slow and unresponsive, verging on frozen, but not quite. In both cases I was able to close applications. The mouse would freeze and then be okay suddenly for two seconds. Using an older keyboard with a power button on it I was then able to get the computer to shut down, maybe three minutes after hitting the power button. Then on restart the mouse and everything works fine, but after the login screen, after logging in, the computer is back to being super slow and nearly completely unresponsive again. After again shutting down as above, both times I then entered safe mode, and then restarted and the problem was gone after restarting again and then logging in and back into normal mode. The problem is I need a reliable computer and have no idea what the cause is or how to prevent it from happening again. Any help would rock. Thanks in advance.