致命错误:调用未定义的函数mysqli_init()

I have a really strange error. My httpd server have been working fine until last Wednesday, when I uninstalled the MS SQL and visual studio C#. When I restarted the PC, Ii discovered that some parts of the Environment variable PATH disappeared...Almost all the problems where recovered, The only one that cannot be adjusted is my httpd server... or the PHP configuration, I don't know. I have already uninstalled the Apache server, PHP and MySql and resintalled them again... I have done this lots of times on other PCs so I'm sure that it should work...but I'm missing something. I have a really strange error. My httpd server