CS5 crashes whole computer

Question

Working in photoshop when using Filter function with Lens correction/vinette correction, noise reduction, or unsharp mask, my computer crashes instanely, no messages, have to reboot, loose all privious work done, I was only working one photo at a time, jpeg file, no enlargement. Due to this problem I send the computer to apple and reinstall the OSX, checked all hardwares, start from a clean computer. can find out why this is, is there a plugin I should install to prevent it from crashing? thank you.
My computer Apple OSX, 10.6.8
Model Name: iMac
  Model Identifier: iMac11,3
  Processor Name: Intel Core i7
  Processor Speed: 2.93 GHz
  Number Of Processors: 1
  Total Number Of Cores: 4
  L2 Cache (per core): 256 KB
  L3 Cache: 8 MB
  Memory: 16 GB
  Processor Interconnect Speed: 4.8 GT/s
  Boot ROM Version: IM112.0057.B00
  SMC Version (system): 1.59f2
Photoshop CS5 extended, no plugins.

Answer 1

Does the whole computer freeze or shutdown, or does Photoshop hang or crash?
If the whole computer freeze or shuts down - then you're probably looking at bad hardware in your system. Bad RAM is by far the most common cause, followed by bad motherboards, CPUs and power supplies.