IE uses 100% of available CPU time

I am having a intermittent problem with IE going into a loop of some sort and soaking up 100% of the CPU time, thus slowing things down and heating things up internally. Things don't stop completely, but they do slow down considerably. I am running windows 2000, ver 5.0.2195 Service Pack 4 Build 2195. My IE is ver. 6.0.2800.1106, update SP1 plus all the latest updates.

The particular IE task affected, doesn't quit, that is it still responds to URL changes and commands within a particular web page etc. but slowly. The one thing it won't do is respond to a normal "close" command either with the "x" button or from the task bar; that is, it responds with a "beep" and refuses to close. The only way I have found to close the offending IE process when this occurs is to go into the Task Manager, identify the IE task which is using all of the CPU time and shut it down from the Task Manager. This gives the CPU a chance to cool off.

I suspect a corrupted file somewhere, but can't begin to identify it. I emphasize the problem is somewhat random and intermittent. My son, who works for Intel, claims the problem is likely related to errors in 3rd party software, i.e. they violated Microsoft rules somewhere, therefore, Microsoft is of no help.

I have been watching this forum, but have not spotted any thing which would seem to apply. Here is my question for you Win 2000 gurus: What do you think of programs such as: http://www.pcdocrx.net, or http://www.asmwsoft.com which claim to clean up unnecessary and corrupted files in windows OS's, and might that help? Also would there be anything else which might help?