CF Server Internal Error

I run CF MX 7 for 2 years on the same PC with Windows XP SP1,
I never have any problems.
And today CF does not work anymore.

The CF services are running correctly, I stop and start,
same problem.

I do not have access to any CF pages, even the CF administrator (CFIDE/administrator/index.cfm)
I use IE navigator, and at top it is written : server internal error.
And CF pages cannot be reached. (I rub under IIS, all HTML pages are displayed)
All my work is stopped.
Do I have to rebuild my PC, or reinstall CFMX7 ?

With navigator Safari, I have : "Jrun servlet error" in the top bar, and 500 null on the page

Thanks for any help.
Pierre.