what you need to do is to edit the system.ini file and delete the entry which is referred to in the error message.
you dont say which version of windows you are using.
assuming you are using win98, on start up goto boot menu (hold F8) when you get the menu, try using safe mode to get windows to load, if not then reboot and enter boot menu again, select start to msdos or command prompt(or something similar) but not the one that says press shift+F5.
once in dos, type edit, once the edit screen appears you will need to navigate using the TAB key and the CURSOR keys (no mouse in dos), you need to goto c:
there in the left pane you should see system.ini, highlight the system.ini and press enter, once in look for the file from the error message, highlight it and press delete. save and exit, then reboot your system.
that should be it mate,
if you are running winXP, you will need a win98 boot disk, put the floppy disk in and restart your computer. choose start my computer without cd rom support. Then follow step one again.
if that doesnt sort it, come back again