|"I would like to connect this monitor to new PC, but it doesn't work."|
Tell us the make and model of your brand name system, or if you have a generic desktop system, the make and model of the mboard.
The specific model of a brand name system is shown on a label on the outside of the case somewhere, or it can often be determined by going to the brand name's web site.
The model, sometimes the make, of a mboard in a generic desktop system is usually printed on the mboard's surface in obvious larger characters, often between the slots.
The model is often also displayed on a logo (graphical) screen early in the boot, but it's often not as specific as the specific model number.
For Dell computers, they have a Service Tag number - the specific model can be determined by using that on their site, or can often be determined there automatically by you downloading some software. The Service Tag number should be on a label on the outside of the case, probably on the bottom on a laptop, on the back on a desktop, and is often also shown in the bios Setup.
Even if the settings in whatever the operating system is on the computer are wrong for the monitor, you should always have normal video while booting the computer before the operating system starts to load.
I noticed when I was looking at new and recent desktop mboards earlier this year that some mboards that have onboard video have a type of DVI port that does NOT support using a standard DVI to VGA adapter with it to connect a VGA video cable connection to a monitor.