But in morning when i come to office and try to RDP that machine it doesnt work.
As suggested earlier, the nic driver could have gone to hibernation or a power state defined by the OS. Just to rule out any errors, if you have the time when you have logged into the Win7 VM, open the vmware.log of the VM from its VM folder and the /var/log/vmkernel and check for any particular packet drops or network related error messages.
