This morning when I had to disconnect the network in the house because of the thunder raging nearby my PC was working perfectly , but after a few hours I reconnected the network I couldn't connect my wireless PC with the router... A friend of mine connected right after the router was on and there was no problem for him. I tried restarting the wlan many times and restarting the computer, but it didn't change anything...
Could it be internet setting that have caused the problem after restarting the router? I can confirm that I was online before the I turned off the router...
So is my network card broken? It can search and find the network, but I can't connect to it, like the password is wrong or something, but it ain't and the signal strength is ok. Right now I'm using a cable to access internet to write this so the card can't be totally malfunctioned...?
" Right now I'm using a cable to access internet to write this so the card can't be totally malfunctioned...?"
The problem is apparently with the wireless so the fact that ethernet works doesn't mean the wireless adapter is working. Though you state that the wireless adapter can detect the router's wireless signal, so that suggests the adapter is working.
It is feasible that the wireless adapter has been damaged by lightning in the area especially if the computer was running and connected to the mains electricity (thus earthed).
You say that a friend could connect to the router (presumably by wireless) so that means the router wireless is okay.
I suggest you look at Control Panel, Hardware, Device Manager and see if the wireless adapter is recognised and not flagged up as faulty with a yellow mark.
Beyond that your issue seems so contradictory that it's hard to know whether your observations are correct or what the issue might be if they are.