Connecting a DVI or VGA Monitor
Your monitor does not have an HDMI connector, but you want to use it with your Raspberry Pi.
Many people have been caught out by this problem. Fortunately, it is possible to buy adapters for monitors with a DVI or VGA input, but not HDMI connectors.
DVI adapters are the simplest and cheapest. They can be found for less than $5 if you search for “HDMI male to DVI female converter.”
Discussion
Using VGA adapters is more complex, as they require some electronics to convert the signal from digital to dialog, so beware of leads that do not contain these. The official converter is called Pi-View and is available wherever the Raspberry Pi is sold. Pi-View has the advantage of having been tested and found to work with Raspberry Pi. You may find cheaper alternatives on the Internet, but often these won’t work.
See Also
elinux has tips on what to look for in an converter.