Slow iMac Due To activitymonitord eating %cpu

Question

Hello to all,
My iMac (Intel, OSX 10.7.5) got molasses slow (dropdown menus taking 30 seconds to drop down, etc.).
Nothing to do with internet, upload, download; all "internal" Mac stuff.
This did not occur gradually over time, but abruptly all of a sudden last night - BAM, s-l-o-w
Consulting the Activity Monitor it showed that activitymonitord was using 98-ish% of the cpu.
Here's what I have (right or wrong, logical or illogical) done:
1- created a new User Account
2- restarted computer and logged on under the new account
3- checked the % cpu usage of activitymonitord, and it was 0.7%
4- concluded that the culprit was something corrupted in the old User Account
5- used Migration Manager to migrate all my "stuff" from old User Account to newly created User Account
6- Migration Manager worked flawlessly, all my stuff was there, looked identical, etc. yippee
7- double checked Activity Monitor and activitymonitord was still at 0.7%
8- took a deep breath and went to eat supper and watch a little TV
9- came back up to computer after a time of about 3 hours, checked Activity Monitor, and activitymonitord was at 8.5%
10- spent 2 hours at computer with Activity Monitor open and just watched the % cpu of activitymonitord gradually rise to
     9%, then 10%, then 11%, 12%, 13%, 14, 15... now sitting at 17%
      very steadily, seemingly just as a ƒ of time, irrespective of what I did or didn't do
My assumption is that activitymonitord will continue to rise under this new User Account just like it did under the old one, and eventually choke my computer to a standstill.
HELP ! ? ! ? !
James

Answer 1

That process only runs when the Activity Monitor application is launched.
Back up all data immediately as your boot drive may be failing.
If you have more than one user account, these instructions must be carried out as an administrator. I've tested them only with the Safari web browser. If you use another browser, they may not work as described.
Triple-click anywhere in the line below on this page to select it:
syslog -k Sender kernel -k Message CReq 'Channel t|GPU D|I/O|n Cause: -' | tail | open -ef
Copy the selected text to the Clipboard (command-C).
Launch the Terminal application in any of the following ways:
☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)
☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.
☞ Open LaunchPad. Click Utilities, then Terminal in the icon grid.
Paste into the Terminal window (command-V).
The command may take a noticeable amount of time to run. Wait for a new line ending in a dollar sign (“$”) to appear.
A TextEdit window will open with the output of the command. Normally the command will produce no output, and the window will be empty. If the TextEdit window (not the Terminal window) has anything in it, post it — the text, please, not a screenshot. The title of the TextEdit window doesn't matter, and you don't need to post that.