This guide was written for the HP Mini 1000 series, but can be adapted for any system with the ability to boot from the network.
Step 1: Install TFTPBoot on a second machine.
You can find the download package and step-by-step walkthrough on Ryan T. Adams blog. Stop at step 6 on his blog. Basically you install TFTPBoot on the second machine, enable PXE booting, and enable DHCP. A side-note you will either need to use a crossover cable between the Mini and the TFTPBoot computer or temporarily disable DHCP on your network while you install Windows.
Step 2: Share Windows Media
Share the optical drive with the Windows media on the second computer and give everyone read access. Also make sure your firewall is turned off during this process.
Step 3: Enable Network Booting on HP Mini 1000
Enter the BIOS settings screen when you turn on the mini by pressing F10 as soon as given the option. In the BIOS settings go to System Configuration> Boot Options. Then enable Internal Network Adapter Boot. Press F10 to save settings and reboot.
Step 4: Network Booting
As soon as the mini restarts and you're given the option to press F12 to boot from the network. If TFTPBoot was setup properly you will boot (somewhat slowly) into a Vista PE environment and you will be presented with a command prompt.
Step 5: Install Network Driver
Now if you were to do an ipconfig, youíre not going to get anything. The reason is because the PE environment doesnít have the driver for the network card in the Mini 1000. First thing you will need to do is download the 32-bit Vista driver for the network card. At the time of writing this, I believe all of the HP Miniís in the 1000 series are using the Yukon Marvell network card. If there are models out there using another network card or this is changed in the future you will need to download the appropriate driver and be sure to note the INF file to use with the driver loader below. You can download the Marvell 32-bit Vista driver here. Extract the contents of the file to a marvell folder on a USB drive.
Plug the USB drive into the Mini. Assuming the Marvell directory is at the root of the USB drive, type the following: drvload d:\marvell\yk60x86.inf
You can verify that this worked by running ipconfig again.
Step 6: Map Drive
Now you need to map the shared optical drive from the computer with TFTPBoot by typing the following: net use y: \\IP_TO_TFTPBOOT_PC\share_name /USER:hostname_of_tftpboot_pc\USERNAME password
Step 7: Install Windows
Assuming the mapping worked correctly, can now run setup.exe from the Y drive and install Windows.