the virtual machine could nort be started because the hypervisor is not running

Can we check the Event Logs on the 2008 R2 Server, System, Application for any relevant errors?

Does your Physical Server have Intel-VT enabled and running in the BIOS?

What is the server, what is the processor?

Can run the following application, and screenshot the output

http://www.grc.com/securable.htm

Check the following articles

http://social.technet.microsoft.com/wiki/contents/articles/194.aspx

http://support.microsoft.com/kb/2490458

http://msmvps.com/blogs/bradley/archive/2008/11/06/the-virtual-machine-could-not-be-started-because-the-hypervisor-is-not-running.aspx

http://fawzi.wordpress.com/2009/04/08/the-hypervisor-is-not-running-hardware-dep-what-is-it/

anser to your first comment is Intel duo CPU /e8500 @ 3.16 ghz
maximum bit length 64

hardware DEP yes

hardware virtulation yes

Ok, anything in the event logs?

how can i access event log?

type eventvwr in the search bar

when i try to access event log from my windows 7 pc to my hyperv server it gives me error RPC server is not avaliable

ah! okay!

so you are trying to start the VM remotely and not on the server?

Does you server have a GUI Console?

Did you run Secureable on the server?

i am connected to server windows 2008 hyper v server suing remote desktop connection

server does not have gui

i was able to run securable on server

So you are using Remote Hyper-V tools on Windows 7 to start a VM?

So you are using?

Microsoft Hyper-V Server 2008 R2 with Service Pack 1 (SP1)

http://technet.microsoft.com/en-us/evalcenter/dd776191.aspx

Are you in a Workgroup or Domain?

how will i check for sp1 is installed or not

yes server is in domain

is workstation in the domain?

It does not matter whether sp1, it's whether you are using Microsoft Hyper-V Server 2008 R2?