“The fans revved and suddenly I could use nothing but the cursor. Had to hold down the power switch to kill all and then re-power & startup. I wasn’t doing anything unusual, but I had 7 apps open and was amid an auto-backup to TimeMachine.”

So begins the first message in MacBook Pro 2011 17″ hard freeze, an Apple.com discussion launched on March 1 by a user registered as “Rensoom.” Three weeks later, the thread Rensoom started had drawn nearly 600 replies and been read more than 105,000 times.

Apple laptops tend to run hot, and complaints of fan noise and overheating are nothing new. But a hard freeze is a serious problem, one that Apple (AAPL) may eventually have to address. A number of owners report that the company swapped their misbehaving MacBook with a new one as soon as they complained. Others, however, have taken matters into their own hands. In a second thread, New 2011 MacBook Pro Heating Issue? (63,008 reads) “Leopotamus” writes:

“There are a few reports online about excessive thermal paste being applied to the CPU and GPU. A few people have voided their warranty and opened up the 2011 MBPs themselves to clean the heatsinks and reapply a more reasonable amount of thermal paste. It has resulted in a 5-10 degree drop in temperatures, down to around 85 degrees C when running under load.”

Also on Fortune.com:

• What the new MacBook Pros mean to Apple’s bottom line
• Apple ‘smoked the competition’ in PC World’s 2010 reliability survey
• Apple’s MacBook (hot) Air problem
  

[Follow Philip Elmer-DeWitt on Twitter @philiped]