No problem 
.
So vCenter need a 64 bit os. that you need to know following :
1- Install VMware Workstation :
2 - Create a VM for Windows 2008 R2 (You will install vCenter component on it).
3 - Create a second VM and install ESXi on it. (It is an ISO, like OS installation).
4 - You can install vsphere client on your Windows 7 or directly on your Windows 2008 r2 (Where vCenter is installed).
All sources you need are here : Download VMware vSphere Evaluation - Free Virtualization for 60 Days
Regards,
Julien.