I tried to use VNC (remote desktop viewer) on a computer that does not have a monitor but failed. When that computer has a monitor, VNC viewer works fine. Also in both cases, ssh remote access works fine. Could anyone advice me what to do. Is it required that the computer must be connected to a monitor in order for a VNC viewer to access it.
Check out http://ubuntuforums.org/showthread.php?s=1d7ec44878f85eedc7376595b188983b&t=1471785&page=2. These people had the same issue as you.
On my I could set the RaspPi to composite. Here is how. On the RaspPi click the RaspPi icon > Preferences > Raspberry Pi Configuration > Display > Composite Video = Enable. I came across this by shotgunning so I don't know what else it does. The HDML is disabled so you'll need to VNC to change it back.
This worked for me. Basically cli into the OS. In my case Raspbian run raspi-config and change resolution. I changed mine to 1024x768 and it worked. Others have said they had to go to 1280x768 to fix.