When the information technology guys discover how painful it can be to upgrade their current PC hardware to Microsoft’s (MSFT)  Windows 7 — the successor to the much-maligned Windows Vista — they may be tempted to switch to Linux or Apple’s (AAPL) Mac OS X.

That’s the conclusion of the product specialists at CRN’s Channel Web — a publication geared more to IT professionals than to the typical Mac user — after running the latest Windows 7 beta through their Test Center.

“On both fresh hardware and on first-look upgrades from Windows Vista machines, Windows 7 met the world looking like a champ,” writes Channel Web’s Ed Mozen in a post published Tuesday. “Upon closer look, though, it appears as though Windows 7 could actually be more of a challenge for businesses than Vista ever was. The upgrade path from Windows XP — which is still the predominant desktop OS in businesses — can be described graciously as ‘ugly.'” (link)

Part of the problem is that you can’t install Windows 7 beta directly from Windows XP. Instead, you have to upgrade to Vista Service Pack 1 (SP1) or later before attempting an install — a process the Channel Web team found to be non-trivial.

Among the scariest quotes in their report:

• “While Microsoft has assured the world that if the hardware works with Windows Vista it will work with Windows 7, the reality is that is misleading at best.”
• “We’ve almost lost count of the number of blue screens we’ve seen in the CRN Test Center during the Windows 7 evaluation process.”
• “We tried to do the upgrade on an Acer TravelMate, but were stopped in our tracks by Bluetooth driver incompatibilities.”
• “On a series of 3-and-a-half year old ThinkPad T43s, an IBM security processor refused to let the notebooks boot up with Windows 7. We needed to crack open a couple of four-year old desktops … to add memory just to try to get a system image.”
• “Across the XP-Vista-Windows 7 landscape, Microsoft has fostered an ecosystem that now holds out the prospect of a mind-numbing number of incompatible drivers, unsupported devices, unsupported applications, unsupported data, patches, updates, upgrades, “known issues” and unknown issues.”

Channel Web concludes:

“One at a time, these problems can be blown off as inconsequential or simply what happens during beta testing and an upgrade process. But, taken together, these problems are appearing all at once after Microsoft’s botched XP-to-Vista upgrade and during the worst economic decline in generations….

“A solution provider can now expect to spend many hours, billable or otherwise, dealing with all the extra pain points brought about by having to navigate through a mine field of three concurrently used Microsoft operating environments.

“Or they could opt to give Linux or Apple’s Mac OS X a try. That’s not as crazy an idea as it may have been in years past.” (link)

During his annual “strategic update” conference call Tuesday, Microsoft CEO Steve Ballmer told Wall Street analysts that while Apple “has probably increased its market share over the last year or so by a point or more,” he was more focused on the competitive threats posed by Linux and Google (GOOG). (link)

In response to a request for comment, a Microsoft spokesperson wrote:

“Customers can purchase upgrade media and an upgrade license to move from Windows XP to Windows 7; however, they will need to do a clean installation of Windows 7.”

Windows 7 is scheduled to ship in early 2010.