If Gateway didn't include a Recovery Partition on the hard disk when they built the machine, the only way forward is to borrow an XP CD, assuring the owner that it's only for the Repair options it has and not installation. It wouldn't pass activation anyway and could harm the owner's own system. What's the problem - many are fixable without recourse to recovery which can affect your personal files?
Restart and keep an eagle eye on the messages that show up before Windows tries to load - look for a Function key to press to start Recovery.