I have given both my daughters Windows7 Netbooks for there homework and have set them as users and me as administrator. I have been hacked in the past by some local little sh....s and it now seems that it may have happened again.

My admin passowrd on both machines seem to have changed which means I cannot alter there useage rights whilst on school holidays. I understand that it is possible to force a new administrator password but I would rather crack the existing one to confirm or not whether I have been hacked, or whether I've just got it wrong. I know what the current passowrds should be but I used there names and the word Allowed and cannot with certanty say that I'm not gettgin it wrong. Can anyone help before I end up spending hundreds sending it off for analysis. I can still get access to the machine via the kids accounts but would like to know one way or another for my own piece of mind. If I have been hacked then I know who it'll be and will be cleaning off my baseball bat! :-)