Everything is OK,but Error 500

I have installed a zen cart and it shows successful intalled to the server,but when i open the home page and admin pages,it shows "error 500" ,what made the "Internal Server Error" ?
What is wrong? How should i do? Please help me!thank you !!

This is a 'catch-all' error generated by your Web server.
Basically there is something has gone wrong, but exactly what ? the server can not be more specific about the error condition in its response to the client.
In addition to the 500 error notified back to the client, the Web server should generate some kind of internal error log which gives more details of what went wrong.

As it should be up to the support personnel of your Host I would contact them and thet should be able to locate and analyse these logs.

Thank you very much ,i have emailed the support personnel of my host and waiting the reply,