I can log on and so can my wife.After running macafee virus scan and getting rid of potentionally unwanteds,my children can no longer log on.
The hour glass just blinks? but never logs on?

Does macafee have a 'back-up' 'quarantine'? Can you restore what was deleted?
Or try System Restore? Start//All Programs//Accessories//System Tools//System Restore (choose a point prior to the scan)

What are the nature of the accounts? Are your's & your wife's Administrator & your children quests?

Check settings via /Start//Control Panel//User Accounts for any problems or changes etc.

My wife and I are administrater and the children are limited.I think an isp was deleted that was necessary for their log on to function correctly.
I tried system restore but it said it was incomplete.And nothing had changed So I went back three weeks and it said the same thing

If a restore doesn't work through McAfee;

Try options thru Start//Control panel//User Accounts

Change an account ...etc...

Or create new accounts.

If there was data & programs on the old accounts you can probably still access them as Administrator and transfer them to new accounts.