Before working on photo's or any other graphics. I would advise you to save a copy of the original image in the DELL folder on the C: Drive.
Working off large photoshop images hosted on H: drive or Media (M: drive) can cause problems when the network is busy, hence the crashes last week. I would therefore advise you to copy your work to C: Drive in to the DELL folder and save your work regularly.
Before going home, you can then copy and paste the work that you have done, back on to a memory stick, your H or Media drive.
I hope that helps and prevents further crashes.