Xbox 360 Video Output: No VGA Port, Use HDMI, Component, or Composite
The Xbox 360 does not have a VGA port. You cannot plug a standard VGA (DE-15 / HD15) cable directly into the console.
Actual Video Outputs on Xbox 360
HDMI (Best): All "S" and "E" models (2010+). Late "Fat" models (Falcon/Jasper, 2007+) also have HDMI. Digital 1080p + audio.
Component (YPbPr) – "HD AV Cable": Red/Green/Blue + Red/White audio. Supports 480p, 720p, 1080i. Included with Pro/Elite bundles. Best for non-HDMI Fat models.
VGA via Official Microsoft Xbox 360 VGA HD AV Cable: This is a special proprietary cable that plugs into the AV port (the large rectangular port) on the console and outputs VGA + analog stereo. It does not plug into a VGA port on the console. Discontinued, expensive used ($30-60). Supports 1080p.
Composite (RCA): Yellow/Red/White. 480i only. Included with Core/Arcade/4GB bundles.
SCART (EU): RGB via official SCART cable (AV port). Best SD quality.
Summary
No native VGA port.
Use HDMI if your console has it.
Use Component (YPbPr) for HD on non-HDMI Fat models.
Use the specific Microsoft VGA HD AV Cable (dongle on AV port) for VGA monitors—standard VGA cable won't fit.