At times, when the computer is in the process of loading and the response is very sluggish, you may find the cause of the problem by looking at the Task Manager.
In a test set-up, after carrying out a thorough check-up, it was found that over 450MB of memory was running with over 400K page faults and counting. The page file usage had run out to the maximum at 1.32G, with 512MB memory, the computer being a 1.6GHz P4 having 1GB fixed size page file, and two hard drives, running with XP SP2. The process of moving the file was tried but with no success, and it was difficult to get away with Explorer.exe freezing up.
At the end of the process, it was discovered that the desktop freezes, but clings to the page file and the memory. However, it could be rectified with the usage of Process Explorer from System internals. It was also found that normal operations could be restored by destroying the initial explorer usage of Task Manager, and another explorer had to be commenced.
On successful destruction of the first instance, by using the process explorer, things settle down with no problem with the running of the second instance in the normal course.
You do not find anything relevant in the logging event until it is started next time. In such a situation, you must realize that there is a corrupted file in the system. You have to devise a way to fix the problem without re-imaging.
More about these problems, beta testing of IE8 and further facts and figures can be found here