kincumber 0 Light Poster

I have looked at this hading in the forum but have not seen a similar case. I have a home network and the second computer is always hard to start I usually have to go through the Safe Mode and Resrart to get it going. But now there is a new problem when I start up the screen flashes on and off continuously up until the boot is complete then the computer operates normally. This is not a practical problem but most ittitating. The computer has legal XP Professional installed.