Client crashing in champ select

Hi,

A couple of days ago i had to clean up my PC (formatted, idk is this the correct English word for it) since it was starting to get kinda slow, so i installed Windows 7 again (used W10 before) and after installing all other programs (word,excel etc...) i downloaded and installed league of legends. The problem started after the first game (test custom game). I was in champ select for ranked game and the game crashed, it opened a window where i would chose to send a report of a bug or no where if i chose to send it it would "report a bug for me" and thats it.

The problem and a really weird thing to me is when the client crashes it doesn't close the client or game but instead it shows me a loading sign while im unable to select a champ or quit the game normaly so im forced to either close it with "Ctrl+alt+delete" command or wait for the game to kick me out and give me a dodge penalty. The bug "goes away" after i get kicked for not selecting a champ which makes the system think that I dodged intentionally. At beginning it was a 40-60% chance of bug happening while after i uninstalled the game and installed it again it happens more frequently (around 70%) which makes me lose even more LP and have bigger waiting time for the game. I have no problem in game or anywhere else except in champ select. It is really frustrating that I have a 50-50 chance to win a game when i get in one but i have a 30% chance of actually getting into one which makes me lose more LP.

I hope someone can help me with the issue, until then i guess ill wept my LP

R.I.P. +/- 60 LP