Try this: Shut down, put in the installation DVD again and then boot the computer to the DVD. Go to the installation screen again and run the "start-up repair" option in the bottom left corner.
It could also be that you need the latest drivers. What make & model computer do you have? You should be able to get the drivers from the manufacturers website and if you tell me make and model I can help point you there.
Also which OS version (Home Premium, Professional, Ultimate) and bit-size (32 or 64) did you install? Many drivers are 32 or 64-bit specific, so get the right one.
As for your data, unless you completely reformatted before install, it can likely be recovered from windows.old by running a specific fix-it tool from Microsoft found
HERE. But your computer needs to be stable so don't do it if your computer is still constantly blue screening.