Hello Papercutter ~ I read your story with much interest. You have a lot of drive or at least energy if you can spend hours cutting paper into tiny bits. I was waiting to hear you say you are collecting them, sorting them by color to create a collage' or mosaic art piece. I keep thinking, you have all that wonderful material you are making ... you are driven to make it, perhaps there is a hidden artist in you. I imagine you use this time to either zone out, or are intently thinking while you are doing the paper cutting.
I think it is a fascinating aspect to the world you have created for yourself. Maybe consider that there is a purpose for this. You are getting ready for something to happen. I am very intrigued with your pass-time.

As to your weight & desire to change, exercise, feel better, I think you are half way there. Wanting to do this is a huge thing.
I am a big believer in taking very baby steps when we want to make big changes. Remember who you are doing this for; YOU!
Walking is an excellent 'go to' to get started. The end of the driveway, the end of the block, around the block. Do it at your own pace, but ...do it! You know you want to, and if a cheerleader is what you need, or want to be accountable to someone, so they know you are trying, you have come to the right place. There are many here who would love to hear that you are taking control of this & making the changes you want.

The computer, in my opinion, and I am sure I am not alone in this, is a crutch, a drug, an addiction, just like those chips you like to eat. Your body craves them. These are things you can also address a little at a time. You can actually do this; cut yourself some slack.
Be mindful of the time & limit yourself, a little at a time, how much you are on the computer. Turn in on later in the day, off earlier in the evening. Listen to music or other programming to keep yourself busy.

I hear in your voice, a person who is ready to make a change. Don't forget that every single day is a new day that you can do one small change-up in activity. If you have a bad day, don't forget, you get another chance tomorrow.
I really am excited to know you & look forward to hearing updates when you are ready to do that.
Best of luck to you Papercutter, so happy you found PC.