No, you cannot sue an employee for not doing his/her job: your only recourse would have been to fire her sooner, as soon as you noticed her not doing her work (unless she had a contract preventing her firing, you could fire her at will). If she *deliberately* sabotaged you--erased files, stole money, defamed you to customers, etc.--you could sue. You could even sue for certain negligence, or unreasonable carelessness, such as if she filled out checks incorrectly, giving employees too much of your business's money. But simply failing to do her job does not give rise to liability under employment at will, since employment at will (the law of this country) supposes that the remedy for a bad worker is termination. You need more than her failure to simply not do her job, but rather need some deliberate, or at least unreasonably careless, specific act or ommission to potentally hold her liable.