computer starting

check the startmenu->programs->startup to see it there is a shortcut to c: if there is delete it.
any shortcuts in the startup dir will make the program run at startup.

If I understand correctly, when you boot the PC, it opens up to Windows Explorer showing the contents of the "C:" drive.
You say there is not a shortcut in the startup folder.
Are there any programs in the startup folder?

If Explorer, or Windows Explorer is in the Start Up section of the start menu, that would cause the behavior you are seeing.

They could also be in the registry under the run or runonce keys.

If have Windows 98, you can run msconfig, and see what programs run at startup. If Windows Explorer shows up on the list, uncheck it, apply, and reboot.

Note: Explorer is the primary interface for windows, Windows Explorer is the file manager.

i know on basic installs, of win98 , if you happen to have a window exploring or browsing whatever, and if you shutdown the pc, or reboot, without closing the window, it will reappear when yu start up again.,

that may not be applying to you, Idont know if everything time you see the window, you say to yourself "dammit, let me restart and see if it goes away" and then i dont know if you are not closing it before you restart, chances are that you probably are closing it, and thats why youare asking for help, but if i happened to be right about you not closing it and then restarting, Give me those PointZ :)