I recently got a new (to me) Windows 7 computer that was put together from used parts by a computer guy. The first problem I ran into was that my old modem did not work for Windows 7. While trying to figure that out, I switched the monitor and the ethernet cables back and forth between my old Windows XP computer and the new Windows 7 computer several times. The display for the Windows 7 computer was fine the last time I used it. My new modem came today, so I again hooked the monitor (and the new modem) to the Windows 7 computer, and turned it on. There is no display, the "no signal" sign comes up. The monitor still works fine on the Windows XP computer. What could the problem be? I changed the battery and reseated the memory cards, there's nothing extra in the computer besides the graphics card, and it seems to be properly seated. There is a dvd drive that sometimes has to be opened manually. I checked all the connections for the monitor, mouse and keyboard, there does not seem to be a problem there.