I have successfully installed ESXi 3.5 in a Dell Vostro 200, a cheap entry-level desktop pc.
The Intel 82562V-2 motherboard integrated network adapted uses the new e1000e driver, so it’s not supported by ESXi, I had to use a Intel 100S network pci card.
Intel 82801IR/IO/IH (ICH9 Family) 4 port SATA IDE Controller: Supported
Intel 82801I (ICH9 Family) 2 Port SATA IDE Controller: Supported, but this box uses a sata cdrom, and the installation will fail using this drive, so you will need to install using a external usb cdrom, from a PXE server, o remove the HD and plug in a supported box and install from this box as I did.
ESXi will not recognize the cdrom.
After that , I’m currently using 3 VMs at this box.
Carlos