i want to connect to a multiple OpenVPN server (apprx 100's) from openvpn client running in a single computer? OR a How many instances of openvpn client can be run in single computer which will be connected to the different remote OpenVPN server ?
Technically, yes. It is possible. I'd need 100 tap devices, thus 100 ip configurations, possibly all bridged together.
You should consider letting the 100 remote machines connect to your central computer as clients instead the other way round. Would mean alot less headache configuring the central server.
But as noted in the comment, VPn might not be the best solution for your problem. In some cases P2P is the better way to go.