Windows client glitch?

So this glitch is weird because I have no idea what exactly causes it but whenever I would shut down my PC completely or restart it and open up league, everything works normal until I log in. When it starts loading up the main page with everything displayed it would cause my whole PC to freeze? As in I can't move my mouse, the screen freezes, my illuminated keyboard freezes as well, and if I was watching a video, it would freeze but the audio plays in the backround still and idk. This only happens after my PC has turned it self back on from booting and only lasts like a minute or two but is very annoying. If I were to just put the PC to sleep then it works fine. I have tried updating my java and anything else I would of thought might of been the problem but it still happens.