My change never take effect

Recently, I just switch windows 98 to Windows2k professional, my machine is in our department network, every time I put any shortcut on my desktop and reset my printer default setting, after I reboot the computer, everything is back to the original settings, the shortcut is gone and default print is switch back to the old one.
Sorry I only have 10 point left. I don’t know how this happened.
Please help!