Desktop loads, then unit freezes with fans on high speed

Question

I've read through the other posts, but this problem seems different enough to this newbie that I started a new question. Thanks for any wisdom/help you can pass along.
The unit had been working normally (if a little slower) until this weekend when it started doing the following each time I attempted to start up:
1) All start up proceeds as normal
2) I log into my account
3) Shortly after my desktop loads, the cursor freezes and the fans begin running at high speed
4) I hold the power button and the unit shuts down
I've tried this three or four times since and the cycle repeats itself each time, never allowing me to get beyond the loading of my desktop.

Answer 1

The are a couple of things to try. First, make sure tha there is no dust clogging your vents. Second, reset the SMU:
1. Shut down the computer.
2. Unplug the computer's power cord.
3. Press and hold the power button for 5 seconds.
4. Release the power button.
5. Attach the computers power cable.
6. Press the power button to turn on the computer.
Third, reset the PRAM.
If none of these works, try using Disk Utility:
1. Insert the Mac OS X Install disc that came with your computer, then restart the computer while holding the C key.
2. When your computer finishes starting up from the disc, choose Disk Utility from the Installer menu. (In Mac OS X 10.4 or later, you must select your language first.)
Important: Do not click Continue in the first screen of the Installer. If you do, you must restart from the disc again to access Disk Utility.
3. Click the First Aid tab.
4. Click the disclosure triangle to the left of the hard drive icon to display the names of your hard disk volumes and partitions.
5. Select your Mac OS X volume.
6. Click Repair. Disk Utility checks and repairs the disk.
Then, when you are booted from your internal, Repair Permissions from your internal drive.
Please post back with results,