I set up PC with 2 network cards, connected to the same LAN. I can connect to this PC (e.g. by remote desktop) only via ip-addresses. Accessing by hostname does not work.

Why is this the case?

UPDATE: Full environment 1. PC with 2 hardware network adapters.
2. On this PC installed VMWare Workstation. Created 3 VM's, networked by "bridged" network setting in VMWare.
3. In LAN all ip-addresses given from DHCP.
4. Win2k8 on all hosts (both physical and vitrual).
As result:
1. PC has 2 ip-address (e.g. 192.168.1.71 and 192.168.1.72). PC available in LAN by ip-addreses, but not avail by hostname.
2. VM's has own ip-addr on each (e.g. 192.168.1.73, *74, *75 etc). They are available from LAN by their ip's, BUT not by their hostnames.
How can I access to PC and to VM's by hostname?