Presario dead after Norton install

Compaq Presario R4000, running XP.

I Installed Norton A\V 2007 last night and was running a full scan when the battery died and the system shut down. (Norton had found and fixed a couple of trojans). Now when you power up, you get the Compaq flash screen (with f10 setup and f12 network boot options) but from there it goes to a black screen with a cursor flashing in the upper left corner.

Will not boot from CD.

Help!!