User Account Disappreaded Setup

We bought a Sony laptop running Vista home for my father and set it up for him. Unfortunately he died before he could use it, so I have inherited it. It was distressing seeing his name all over the thing, so I created a new user account in my name, logged in as that and then deleted the old account in his name. A warning did come up saying that he was still logged in and some data may be lost, but as there wasn't much there I went ahead anyway. All the files under his account had disappeared (including one or two I realised i wanted) as had all his settings and even some software setups. Nothing in the recycle bin; I have run a couple of lost file recovery programs which only find files that have been consciously deleted. Where have his files gone?