Wifi signal low only on my computer

Hello,
Suddenly my laptop wifi decreased considerably but before that, I was using it perfectly. 5 bars and many networks were available. But yesterday I do not know for what reason the signal went weak and I'm only getting one bar or the bar signal is empty and plus I can't even see other networks. I didn't sleep yesterday because I had to fix this. I've checked everywhere on internet but couldn't find help. I have downloaded all the wifi/wireless drivers but nothing worked. I have even updated my drivers using driver pack solution but still it does not work. Can someone help me fix this problem?
Thank you for assistance :)