Officially ESXi only supports the hardware listed on it’s Hardware Compatibility List but it will run on a wide variety of hardware not on that list. You will not find and desktops or laptops on this list as only server hardwar eis supported. It really depends on your CPU, if your laptop has support for Intel VT or AMD-V extensions that are included in many newer desktops and laptops that there is a good chance that it will run. By default these are usually not enabled and you have to go into the BIOS of the PC and enable it. If you do not have these extensions it will usually take a very, very long time for ESXi to install and boot. Additionally you should have at least 1GB of RAM and preferably more. You should have no problems installing it on a IDE drive but It may not recognize the SATA controller though. However you cannot create a VMFS partition on a IDE drive and you will need to use alternative storage (i.e. iSCSI/NFS).
A better way is to use VMware Workstation on your laptop and install it inside a VM, again you will most likely need the virtual extensions I mentioned for it to work properly. Download the free 6.5 beta which supports ESXi 3.5 U2 and create a VM, mount the ISO and install it. Also when you create the VM make sure you choose a SCSI adapter for it so you can create VMFS volumes. After you create the VM you should edit the vmx (config) file and add the following lines to it.
ethernet0.virtualDev = “e1000″
monitor.virtual_exec = “hardware”
monitor_control.restrict_backdoor = “true”
There are some really good tutorials on how to do this below: