Microsoft is ratcheting up for the launch of its latest and greatest operating system next week, riding the heels of Apple's earnings report, but the Mac maker shouldn't fear the new salvo from its long-time arch-rival.

The Redmond-based software firm is rolling out Windows 7 in stores and on new computers this Thursday, but the debut won't intrude on Mac sales, according to Brian Marshall, an analyst at Broadpoint AmTech.

Marshall analyzed the impact of major Microsoft operating systems (OS) launches and the associated impact on Apple's Mac computing sales (both notebook and desktop) the last 10 years including the impact of Windows 98, Windows 2000, Windows XP and most recently, Windows Vista.

The conclusion was that no negative correlation exists on Apple's hardware sales when Microsoft launches a new OS.

Ironically, we believe new OS launches from MSFT may have even acted as a 'delayed accelerant' to AAPL's computing sales, Marshall said.

Marshall also predicted that Apple has the ability to potentially double its computing market share on a global basis from roughly 4 percent today to 8 percent over the next five years. Apple should be further buoyed the iPhone, which ranks next only to Mac in making revenue.

With the iPhone now available in 80+ countries, the global ramp has just begun, he told clients.

Cumulative shipments of the iPhone since its June '07 inception now total 26.4mil units.

Marshall named Apple as best positioned company in technology sector as it continues to gain share across its major product lines as well with continued penetration of international markets.

The numerous catalysts on the horizon for Apple include China iPhone ramp and the long-expected netbook/tablet launch, according to Marshall.

All leads to the bullish forecast for Apple's first quarter of fiscal 2010, which, according to Marshall, will see the revenue ranging between $11.1 to $11.3 billion and earnings per diluted share from $1.58 to $1.63.