My windows Vista does not load and reboots itself?

Ok, I've a vaio TZ whith a Hard Disk Drive and last night I turned my computer off as always, when I tryed to turn it back on it didn't! It loads and just right before the vista logo appears, it reboots itself!! When I saw what drivers were loading, it loads fine until crcdisk.sys appears, then it stops. The screen goes black and you can see the arrow, but then reboots. It does the same thing over and over and over again by itself. Please help me, I'm studying outside USA and don't want to have to mail it. Sadly, as a Vaio, it doesn't come with the Vista CD.