You should be able to restore the default OS that shipped with the netbook using the recovery partition. Try tapping F4 repeatedly at boot, it should launch recovery. Check first under Start menu- All programs for something called Samsung Recovery Solution (or something similar) and try to launch recovery from there. See this page for a guide. How To Use Samsung Recovery Solution 4 my samsung
Factory restores are usually destructive, so back up critical data before attempting this. This process will recover your computer to the condition it was in when you unboxed it, including all Samsung bloatware. If you want just the OS, you'll need a disk, google for a clean iso.