text: this message appears when i have installed win98 in my pc? "this program has performed an illegal operation and will be shut down, contact the program vendor"  what does this message mean and ask me to do with my pc. any solution please? some type of installed software is failing.  it could be anything that you've installed, including the operating system.  are you saying you just recently installed win98 or it's always been there?  whatever software change you made recently is likely the culprit.  it could be anything such as installing a game.  it could also be a corrupt dll.  if you can figure out what program is causing it, you should reinstall that application to try to fix it.  try to narrow down the software that's causing the bug.  start up in safe mode first, to make sure it isn't the operating system.  when you reboot the computer, press f8 continuously until the boot options menu comes up, then choose "safe mode" or "safe mode with networking".  if it starts fine after that, then it's likely something other than windows that's failing.