I agree, take the computer away.
Set up a chore system. Do you only have one?
On the weekdays what do you want him to do?
Mine scoop cat litter, feed the dogs, set the table and clean dishes depending on whose day it is to do what I have three at home.
Be in the room and help him. Even my 12 year old has trouble with really yucky pans and my 9 yo is still drying while I wash. He just doens't get things that clean yet.
If you want him to clean his room make it reasonable. "Clean your room" is too big, it's too much. Break it up. Tell him to pick up all the clothes, then all the Lego's, little Army men, crafts, etc.
Or
Have him do it in sections. Do everything on the bed, in this corner or that.
If you want him to dust in the living room , Show him how you want him to do it.
Then when it is his day to do it hide quarters and dimes under things so when he dusts he gets a reward immediately.
Do the same in the bathroom. Show him.
Tie his computer time into whether or not his chores are finished. Same with friend time.
Mine is 9. On Saturday mornings his chores can include
Cat litter, sweep cat room
vacuum, dust living areas, wash windows,
pick up all piles of stuff.
bathrooms, sinks, toilets, and sweep floors
dishes: load the dishwasher and dry, counters, set the table, If he only has a couple cups and bowls to wash he can handle those, plus the knives that don't go into the dishwasher. I usually wash the greasy pots and pans, he dries
He has different chores for different days.
Since I have three while he does kitchen duties another does cat duties and another does the dogs. They rotate every day.