First, you shouldn't have to remote in to your office computer so the error goes away. I mean it may work, but you shouldn't have to.
A few things. Just ideas, can't say they will work.
First, RAM is cheap. I would add at least one more. SQL loves to eat RAM. There is a way to limit how much it takes. When you get the error, check how much RAM SQL is taking using your task manager on the main computer. Certainly, a reboot would fix that, so it could be part of it. Rebooting the other computer shouldn't make a difference but a fresh connection may.
If you find out it's the RAM, I can remote in and possibly limit the amount of RAM Express is taking. I would have to research it. I can do it easily on 2008, but not sure how to on XP Pro. I am sure it is out there on the net somewhere. But, I would have to do it for you.
I WOULD TRY THIS JUST FOR FUN:
Have you tried mapping all the drives on each computer to the server so the connection is constant? Or whatever it does, lol.
