HP's business support site says to use "system recovery to restore the computer to original operating condition," and further goes on to define system recovery as formatting the windows partition of the hard disk and re-installing Windows, the applicable drivers and software for the machine.
Now the fun part. The HP Slate 500 comes with two DVD's for restore purposes, one is Windows 7 Professional 32-bit and the other is the drivers and software disk to make all the extra bits like the camera and touch-screen work correctly. Neither of these disks have an automated system recovery procedure though I've seen on the various HP message boards that installing off the Windows DVD and then installing all the software from the auto-run procedure on the drivers and software DVD accomplishes a similar feat.
That said, I had trouble getting my external USB-connected DVD drive to boot the Windows DVD that came with the Slate (as it turns out HP support tells me that the DVD I have is bad) so I looked around a little more and heard about a USB thumb drive system recovery option from HP (you may have seen information posted elsewhere as well).
I spent about 3 hours on the phone with HP business support and here's the important piece of information that makes this long post worth the time you've spent reading it...
HP support can overnight you, for free (assuming you own or are supporting the HP Slate 500 and have the relevant ownership information) a USB thumb drive that does an automated system recovery.
The HP support rep can find the part number 638737-001 in their internal "CD order tool", specifically:
Item Number - 638737-001 KIT
Item Description - Windows 7 Pro 32-Bit Slate 500 USB STICK
When you receive the USB thumb drive you have to do the following:
1) Fully shut down the HP Slate 500
2) Plug in the HP Slate 500 with the AC adapter
3) Plug in the USB thumb drive to the USB port at the top of the device (it won't look like it fits all the way in but it does)
4) Boot the device and hit the "-" hard key at the top of the device to go to the boot menu
5) Select the boot device options by scrolling with the "+" and "-" hard keys at the top of the device and confirming your selection using the "home" hard key at the top of the device
6) Select the USB thumb drive from the boot devices using the same keys as in step 5
7) Next through the HP system recovery UI, selecting the options you want (Note that Tab functionality is accomplished with the "Keyboard button" hard key on the left side of the device)
8) When the device is ready to reboot, leave it plugged into AC power, remove the USB thumb drive and use the "home" hard key to tell the device to reboot
After that, all the rest is automated and after waiting a bit for the system recovery to complete you'll be asked for a new Windows user name like you were (or maybe someone else was if you're doing support for someone) when you started using the device the first time.