which program is trying to end?
When you get the message, click CTRL+ALT+DEL to bring up the Windows Task Manager and in the Applications tab see what programs are running and whether they are "not responding".
i downloaded microsoft anti spyware and this seemed to fix a lot of my problems. it found quite alot of bugs that were spoiling my registry keys etc. anyway, now im getting an end program msg when i disconnect from dial up. my pointer stalls and so do some of my programs including explorer. any help would be much appreciated.