System Recovery

Hi,
Can someone please help. I have checked through this forum and have seen the same problem appear but on different computer softwares so don't know if I need to follow the same instructions.

I have a desktop computer (ei system 204-uk) which was purchased about 3 years ago. Anyway as the computer was running slow I saw the words "system recovery" and decided to click and follow the instructions. It was only when it got to the words "thank you for purchasing this computer" and was asking for a user name did the warning bells go off in my head and by that time it was too late. My computer restarted and all my data has now been lost ie documents, pictures, itunes etc.

Is there any way of retrieving this or has it all been lost forever.

Please, please, please, can someone help.

I am more interested in retrieving my pictures as off the family and the new edition.