A program is running in the background of my computer and keeps interupting 
other programs, such as scan disk. How can I find out what program it is and how 
can I stop it from running?

Best go to :www.sysinternals.com (the site appears to be offline right now but 
see that Google knows it: ://www.google.com/search?hl=en&q=sysinternals)


Download filemon, sysmon and regmon.

These are utilities that do exactly wat you want.

1. Stop as many processes on your computer as you can. This will reduce the 
amount of activty recorded. 

2. run the program and capture the processes. Start scandisk, and wait until 
your background program stops scandisk.

3. Stop capturing activity, and search through the logfile. (eventually post 
it, so I can inspect it) Do not be overruled by the ammount of information you 
see appearing. After looking at it for a while you can see the structure.

If you're running Windows 98, ME or XP you can click on "Start", and click 
on "Run".  In the run dialog box type "msconfig".  From there, go to the 
Startup tab and in here is a list of items with check boxes.  All these items 
are programs that start when your system boots up.  Unchecking the unneeded 
ones will free up system resources and probably allow scandisk to run.  Some of 
these are critical system services, so you may want to check with your computer 
manufacturer to find out which ones are needed and which ones aren't.  If you 
are running Windows 95, 2000 or NT you can access this through your Registry 
Editor by clicking on "Start", going to "run" and typing in "regedit".  From 
there, access the 
registry "HKEY_LOCAL_MACHINE/Software/Microsoft/Windows/CurrentVersion/Run" 
also RunOnce, RunOnceEx, RunServices, and RunServicesOnce.  Deleting the 
Registry keys from there will disable the programs from starting up.

For a partial list of items that start with Windows, check here:
http://www2.whidbey.com/djdenham/Uncheck.htm

Secondly, if you are uncomfortable removing these items, a simpler way is to go 
into Safe Mode and run Scandisk/Defrag from there.  You can do this by 
restarting the computer with the left control key (CTRL) depressed while 
booting, or continously tapping the F8 key during initial bootup.  This will 
take you to the Windows Startup Menu.  Safe Mode is option number 3, so you 
would hit 3 and enter.  From there, it loads Windows with minimul device 
drivers and no programs running in the background.  After disabling your screen 
saver, you should be able to run Scandisk and Defrag with no problems. 

For more information on Scandisk, visit here:
http://www.computerhope.com/software/scandisk.htm

Hope that helps!

All of the above will do the job, but are cumbersome. The culprit is usually "Live Update" of Symantec's Norton Antivirus, or another Symantec 
program where you can set Live Update to check for updates automatically. If you have Norton Antivirus, in the program select Options, then
 Live Update, turn off the "Auto." You may need to reboot to effect the change. Change back when scandisk has finished.

The other thing you can do is hit Control, Alt and Delete on you keyboard all at once. A list of programs running in background will appear. You want to 
remove all of these except "Sys Tray" and "Explorer." Highlight one of the others, click end task. Repeat as often as necessary to remove all items
except ones mentioned above. Some may resist "ending," but you'll get notice and you'll choose to force it to end. When complete, run scandisk. Then 
reboot to restore system to original state.

Lastly, a virus can interrupt scandisk, so make sure you have UPDATED Antivirus software, and run a Complete Scan.

If you're running Windows 2000 or XP, press control-alt-del and it will 
bring up the End Task window.  Do this when the problem occurs.  I forget 
exactly what the tabs are there, but I think there is a tab named Processes 
in Windows 2000 and you don 't have to click a tab for Windows XP (but 
the Performance tab is always interesting).  If you click there it will show 
you what percentage of your processor's power is being taken up each 
program/process.  What you're looking for is something that is using up 
over 80% of the CPU.  If what you you find is the System Idle Process, 
don't close it.  But if you find anything else that is taking up so much 
processor, that is where your problem lies.  Click and highlight the 
program or process that is doing this, then click End Task.  That should 
solve your problem.