Janey,
I haven not had the opportunity to have played with you but I'm sure your a fantastic person a good player and great XI member ! Remember there is always light at the end of the tunnel enjoy life, live it to the fullest and always be happy no matter how bad things are. Do what you want to do be kind to everyone and you will be re-paid ten fold. As far as your machine turning off it could be a overheating issue with vid or power supply maybe a bad overheating ram chip... I would start by reseating the video and ram chips see if that helps....or removing any dust in the system.
We at XI are here for you if you need anything just send us a PM if you need anything!