How to exorcise the ghost in my machine (computer question)

I hadn’t done maintenance on my computer in a couple weeks, so I did the full spectrum today. First I ran Spy Sweeper, which caught 41 items. Then I ran Ad-aware, which caught an additional 10. I removed them all. I deleted all cookies and all files, including offline. Then I restarted the computer. I used Ctrl-Alt-Del to see what was running, and it only showed what I was expecting- Explorer, Ccapp, which has to do with my Norton antivirus protection, and Sysytray, which I do not know the use of but it’s always there. I ended them all except Explorer, set up a defrag, and sat down to watch TV in the other room.
An hour later, it was only at 66%. I watched another show. BBC America’s Friday nights rock! the Saint, the Avengers, and The Prisoner. Yum. Anyway, at the end of the next hour, it had progressed to 87%. As I sat down in front of the computer, the defrag restarted with a message about drive contents changing. I had touched nothing, and nothing was running so far as I can tell. It made it back up to 87% in about a minute, then proceeded according to the Details page (stuff was turning blue), but then it restarted itself again. I stopped it and came here.
So if nothing is running, what’s changing? I just checked with Ctrl-Alt-Del and it says Explorer and Straight Dope and nothing else. I am at a loss.
As a potentially related second question, my Norton Antivirus is set to Live Update and scanning, so it should be aware of and block any viruses incoming, or so I am thinking. If it’s on constantly, do I still need to do a scan, and could I have a virus? I’m going to go do a scan while I wait for answers, just to be safe.
Thanks!
HennaDancer

First, what operating system are you running? From your message, I’m assuming your running Windows 9X (95, 98, ME). If so, then the only two things that should be open when you CTR-ALT-DEL is Explorer and Systray. The Systray (System Tray) is the little bar on the bottom of the screen, right where the clock is.

Run Defrag with only those two parts open, if it restarted then it saw something write to the disk. This is not a really big deal as long as it doesn’t happen all time. It could just be the OS writing the the virtual memory. It will automaticly start back up if it stops. Just to warn you, if it stops 10 times, it will bring up an error message saying to close your programs, just tell it to continue.

If you are running a diffrent OS then Windows 9X, then this will not apply, just let me know which one your running and I’ll tell you what to do then.

It’s Win ME.

The Windows defragger is a piece of crap, and will restart if there is anything like an antivirus program or screensaver running in the background. Download a free copy of Diskeeper Lite, it is much more stable, more efficient, and quicker too.