I've been asking myself that question off and on ever since I got my current Dell desktop computer about a year ago. Most of the time I've been pretty satisfied with the performance, but sometimes it just starts responding slow to the point of being unusable. I finally got around to doing something about it and what I found was that MS Office has a program installed along with it called find fast which creates an index of all Office files so that they can open quicker. Apparently find fast has been rebuilding that index every afternoon after lunch, and if I'm trying to do anything at the time then it's just tough luck for me. By the way, a tell tale that this might be a problem is that you can hear the hard drive clicking away continuously as the indexing program is accessing it over and over.
Anyway it was simple enough to turn find fast off using the instructions found on the Microsoft website here ;
Turn Off the Find Fast Indexer
To turn off Find Fast, delete the Find Fast index files by following these steps:
1. On the Start menu, point to Settings and then click Control Panel. Change to "Classic View"
2. In the Control Panel, double-click Find Fast.
3. In the "Index for documents in and below" list, click the first item.
4. On the Index menu, click Delete Index. In the Delete Index dialog box, click OK. When you are prompted to delete the index, click OK.
5. Repeat steps 3 and 4 until no more indexes are listed.
6. Click the Index menu. If the Run When I Log On check box is selected, click it to clear the check box.
7. On the Index menu, click Close and Stop. If you are prompted to stop Find Fast, click OK.
My computer responds a lot faster after lunch now and opening an office document still isn't too slow. I don't know what Microsoft was thinking when they included this thing. The only speed bump in the process of turning off find fast is that you have to enable the "Classic View" of the windows control panel to get to find fast to turn it off.
I was able to track this down by using a free program that I downloaded from Microsoft called Process Explorer . Process explorer is kind of an expanded version of Windows task manager (that you access by doing a control-alt-delete BTW). You just leave process explorer running in the background and when your computer slows down you just take a look at what is hogging up your system resources. In my case find fast wasn't really using much CPU time but was slowing everything down by accessing the hard drive more or less continuously. This was clear to see when checking out the system information graphs.
Anyway, if I have helped even one person free their computer from the resource hogging evil which is Microsoft Find Fast then the world is a little bit better place. On a more positive note for Microsoft the free Process Explorer program is a pretty good replacement for windows task manager.
Apparently (according to the Microsoft website) there is also a version of find fast that is installed with some MS operating systems which I would guess might cause similar problems. Directions for removing this little nasty are as follows:
In Control Panel Select Add / Remove Programs Select Add / Remove Windows Components Uncheck the Indexing Service
This is obviously just one of many things that can make your computer respond slow, but Process explorer can probably help you figure out any number of similar problems. Good luck.