Sony UX Series computers - CD/DVD drive?

[a_medico]

How does one format and reinstall OS on these systems?

http://www.amazon.com/gp/search/?node=565108&keywords=Sony%20UX%20Series

They don't even seem to have a cd/dvd drive. They do have an option of external drive but then how do you install an OS after formatting?

[sashijoseph]

They probably have a hidden partition with the equivalent of Ghost in it.You may be given an option in the BIOS of restoring to factory settings or sth,which would use the preloaded image in that partition.