SQL Server 2008 R2 does not replay

Hi,

I have updated my system from PHP 5.2.6 to 5.4.13 and it works. (I used to use mssql driver and I'm using sqlsrv driver now).

The thing is that sometimes, SQL server 2008 R2 does not answer.

The PHP script keeps running waiting for an answer, and if I am on the SQL Server management studio, it pushes me out.

I do not know what can if be, but I switched the PHP version on the IIS to start working with mssql driver again and it works fine.

Any help? Thanks.