Microsoft Corp. said it is renaming upcoming versions of its Windows operating system and Office business software in a move that emphasizes the software giant's push to Internet-based computing. Microsoft will dub its two flagship products Windows XP and Office XP, with the XP standing for "experience," the Redmond, Wash.-based company said. Windows XP, previously code-named "Whistler," will be launched in the second half of this year, as announced earlier, Microsoft said. Microsoft also confirmed that Office XP, which had been called "Office 10," will come out by midyear. Microsoft shares rose $1.13 to close at $61.94 on Nasdaq.