Although it doesn't appear like the monitor is at fault, try swapping in a known good monitor to see if it works normally. If not, and because you can't reach a screen where you see a basic Windows display, it appears like it's time to perform a reinstall of the operating system.. If you've got the Vista reinstall disc, which Dell normally provides with their systems, plus the driver/resource CD, you should be able run a repair install using the Vista disc.. A repair install should allow you to reinstall the operating system without damaging your personal files.. If the repair install doesn't fix the issue, then a full format and reinstall of the operating system will be necessary.. Remember to install the drivers from the driver/resource CD after the operating system is finished installing.. Once that's done, you can use your backups for replacing important, personal files, pictures, etc.

Hope this helps.

Grif