Did my scan to get rid of all viruses and my folders with pictures so empty. Nothing in them. Then a thing... .not a folder says zipped. I found I can access some of the pictures in my email but my sons wedding pictures are gone... .
Downwhim, did you find any viruses on your computer? The reason I ask is that there are some viruses out there which target pictures (similar to what the celebrity community is seeing right now) but they don't necessarily delete them, they just hide them. If you open the picture folder and right click, go to properties and see if the hidden box is checked.
A lot of the advice on this page is extremely useful regardless of if it is your ex or a virus as it eliminates opportunity. I would definitely start with changing the wi-fi password because that's the most common password people forget to change.
When I was an IT engineer, we had several software programs that were installed on all the computers in the business. It allowed us to remote into anyone's machine and fix an issue. The part I worry about with you is that if your ex has installed this software, he is able to watch what you are doing on the screen and that does worry me. If you want, go into your programs under control panel and make a list of all the programs you have installed on your machine that you don't recognise. You can PM if you wish and I can verify if they are safe or if there is anything you should remove.
Also raisins suggestion of software is free and is safe. Hard drives always hold a signature, which is why pedophiles aren't safe when they think they have destroyed all the evidence on their machines but would first start with checking to see if they are hidden rather than deleted first and then we go from there.
I will also send you some instructions via PM later where you can check exactly who has been logging on to your computer. Regardless of how someone gets in, there is always a footprint trail that takes a very skilled person to be able to eliminate any trace of them being there.