[Young Spade]

The ASUS pcs come with a restore partition on there so you can restore if you need to at any given time; maybe yours has one too? But yea they stopped shipping CDs and the like.... best bet is a digital download. 

 

[Fallingwater]

A friend has just bought an Acer subnotebook and has the same problem. The store told her to burn her own restore disc using the preinstalled app, but expect the resulting restore disc to be mated to the one computer it came from.
There's also a hidden 12GB partition on the disk. I had a quick look using a Linux live-CD distro, and I think it contains necessary stuff to restore straight from there if need be.