Little screensaver problem(WinXP Pro)

I don’t know what caused ths to start happening, but since yesterday my computer has started ‘acting up’ I guess. I have my screen saver set to come up after 15 minutes, and power saving set to turn off the monitor after 45, but for some reason once the screen saver comes up (the “Blank” one that comes with Windows, by the way) after about 10-15 minutes, my desktop is showing again. I’ve run adaware and have ‘ad-watch’ running, but it’s not catching any problems.
Occaisionally I’ll ctrl+alt+del and there are ‘iexplore.exe’ showing up under the processes tab that don’t show up under the applications tab.
I’m just trying to figure out what to do to make it stop doing this, as it’s mildly annoying. Thanks for any help/pointers