The only time I recall seeing this was if I was running a linux based VM. In which case, once I had focus inside the console window was to press return to force text to appear on the screen.
It's never happened to me with a Windows O/S though.
you need to do some troubleshooting and quick check.
1. is the same behavior is with other vms as well.
2. did you tried to open with webclient too. same issue there too ?
3. Also is the vm still accessible remotely via rdp, putty etc.
Make sure that the selected guest operating system is correct by navigating to "select VM > Edit Settings > Options > Guest Operating system". If it is wrongly set, then wrong VMware tools may installed on VM which turns the screen blank sometimes. Also check the port 902 and 903 works fine.
its for only these VM, all other VMs running fine. all are windows OS.
same issue on webclient also.
vm is not accessible by any mean ping, ssh or putty, its not at all pining.
i checked the VM has correct OS selected under settings.
is port 902 and 903 should be accessible both from the vCenter os and also from the client os vm where am accessing vsphere client.
Yes. it should be. Can you check for Port 903. If 903 is blocked between the vCenter and ESXi host. ie do telnet from vCenter server