Moving my wordpress blog unsuccessfully

Hi

I started my wordpress blog using a domain name but then wanted to move it to my new domain name.

I have moved all files and folders across to my new ftp but unfortunately cannot load the blog correctly and cannot work out what I have forgotten to do or done wrong.

I can see the HTML and text of my blog post but it is not showning my images or theme. I also can no longer log in. I receive this error message:

Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator, [no address given] and inform them of the time the error occurred, and anything you might have done that may have caused the error.

More information about this error may be available in the server error log.

Additionally, a 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request.

I’d be really grateful if someone could assist me.

Thank you