1. Install ubuntu server
1)select the network as NAT
2)set the PC's network as invalid status, if the installing process is stuck in the process of "setting apt".
2. Install rhel
1)select the network as NAT
2)ATTENTION: select the disk as IDE, if your disk is SATA format. I still did not know how to install SCSI disk.
After the installation ,config the network:
http://www.tkk7.com/jinfeng_wang/archive/2009/05/15/270951.html