Control Panel Icons Locked

Windows 98se. If I double click on any icon that has anything to do with the system for example all icons in Control Panel, get message saying “you are not authorised to access these items” Okay I have seen this with Win2000, WinXP etc. but not with Win98. There are no other users,no password to log onto when windows boots up. Could someone tell me how this has been done. I am more interested for a lady who teaches basic computer skills, she has three systems for learning on and she says her students realy mess things up. This would be a good idea if I can lock certain items so students can not open them. Thank you