One solid beeeeeeeeeeeeeeep, or a beep.. beep .. beep, or a sequence of beeps?
Whatever the beeping is, you should look up in the dell website, or the documentation for your model, and diagnose what that beep means.
I don't think the monitor, connected or not, will cause any beeping. Your problem is more early than that, such as a BIOS error, some memory error, or perhaps even a power supply error.
BTW, when you finally get past this beep, you should connect your monitor with a direct cable, and not use some adapter or converter cable. Even a regular old VGA cable would be good (assuming you have those sort of connections) to get you to a point to get the computer up again. Leave the adapters out until you don't have other problems to worry about ... one thing at a time.
I have a Dell XPS 720 that my brother got from a friend.The problem that we had with it is that nothing will show up the monitor. We connected the monitor to the graphics card by a HDMI to DVI-I cord. Also when we turn the computer on there is continuous beep.I have already tried removing the graphics card and placing it back in. I also taken out the ram and put it back in.Any advice will be appreciated. I would love to get this computer working again.