hp ProBook 5310mのDisplay PortはHDMIコンバータに対応してたなう。

PC

hp ProBook 5310m with Display Port converter to HDMI is able to use.
with DELL 24 inch cheap one :)

in my case.
OS: ubuntu 9.10 & 10.4 & Windows XP
HW: hp ProBook 5310m
LCD: Dell 24 inch full HD
Converter: Display Port to HDMI(without power) (bought it in Sim Lim Square)
Note: no need any special setting.