problem with 500 error on php pages of virtual host

[cyril-c]

I was installing linuxmint nadia ubuntu kernel after having doing the test on kde version is geniale, but I had concerns that the 500 error page in php (the html page on) I thought it was Were can be due to the kde version I was in linuxmint 12, I heberger my small site with ispCP omega-, php work, but since I was installing linuxmint nadia without going through an update (I'm my backups from external hard drive to my site), so my problem is that all my php site displays error 500 internal server error, however ispCP is Consus in php and all works, but I spend on the virtual host , well I is no website online and has a sacred problem, only the website in html walking vurtual host and not the php site: '(
someone would have a solution please?