Recently after rebooting a VMWare server , the VCenter Server service would not start  

The description for Event ID 1000 from source VMware VirtualCenter Server cannot 

C:\ProgramData\VMware\VMware Virtual Center\Logs. Look at the vpxd.log

<YYYY-MM-DD>T<TIME> 02128 error ‘App’] [VpxdReverseProxy] Failed to create http proxy: An attempt was made to access a socket in a way forbidden by its access permissions.

Checked NetStat and something was running on port 80. Looks like IIS had been installed with default settings which puts default site on port 80. Changed this to another port , reboot IIS and this fixed the issue