How to let my computer fix trouble with it?

Hello,
I m using laptop toshiba with webcam set inside and volume.
Whenever have wifi I can access any websites and sign in yahoo to video chat with my friends.
I didnt know what happened to it.
Last evening I opened my laptop saw have wifi but I couldnt access any websites, or sign in yahoo as normal.
I tried to lose electric let it reboot and pressed "save mode with network" then i could access some website, but couldnt contact to ask assitant because it said " in save mode : couldnt open this have to let it normal .
I restart let is open normal style is repeat the problem that I couldnt sign in yahoo or open any website as I didnt have internet but in fact if do save mode with networking then can use internet good.
Please guide me now to let it work as normal'
Thank u very much
I tried click restore system to hope can solve some troubles, but the restore system didnt run, if click in that it said auto run ......