I can commiserate, I always seem to have 4 or 5 unfinished projects on my computer table and the things I need for my projects are within easy reach meaning that the children can reach them as well when they have computer time. Or my husband can shift things just enough that I lose a vital piece. Until we get my son's computer back, well I have to share. Plus I've learned to put away my "toys" before I give up my space and I schedule computer time for each child so there are no fights.
I heard the greatest thing on Mission: Organization one time and most of my advice is going to come from that show on HGTV
The organizer said, most information is so readily available on the internet that you don't really need to keep paper. I have no idea what kinds of papers you're trying to keep so I'll touch on the ones I can think of.
The most important thing you can do is install shelves near that desk to put boxes, binders and project baskets on, well out of the reach of the children. Allowing lots of room to intermix decorative items and pictures.
School papers from the kids, Each child should have a decorative acid free box to put drawings and school papers in. Every month you pick the one's you want to save and put them either in a different box for long term storage or into a scrapbook. (Large things that won't fit in either should be photographed with the child.)
Bills, there's a file thingy that has the days of the month on it. you slip a bill into the slot representing the day of the month on which the bill is due and you'll never be late again.
Other papers that aren't reference materials, go into a lateral file or, stacked in-boxes. Mark them Immediate action (things you need to sign and return right away/ your bills can also go here), Action (things you're trying to decide on), and file.
Your filing system:
use red colored hanging files and folders for health and family, Green for income and investments, Blue for bills, yellow for reference materials that pertain to your house and belongings. Other colors will be reserved for projects and interests. Like Geneology of each side of the family, garden plans, Art shows, Family or school reunion planning, info or memoriabilia.
I would suggest you keep all of these files where your husband and you can access them but the children cannot, meaning not in your desk. A locking fireproof filing cabinet is the best place.
You could also set up an action center in another room or on another table or shelf in the same room for the other orgainizational items to keep them away from the computer.
One mom was given a locker looking set up for her children to put their stuff from school in. Each locker door had the picture of the child and the inside was wide enough to set notebooks and project papers in. The back was open so mom didn't have to open the door, she could just turn the whole thing around to empty out the cubbies/lockers.
A young bachelor was given stationary boxes and baskets to empty his pockets into and a place to sort the mail with a shredder right there to handle junk mail. The were kept in a built in book case that had typically been his catch all and often ate his wallet and keys.
Activities such as scrapbooking, games and othere things you may do there should have their own shelving zones and lateral files.
send me a message here if you have a particular problem, I've seen them all but I can't think of every prospect in this small box.