Well if you haven't exercised in a while start by walking. Also hand weights are nice to keep muscle toned. Exercise doesn't have to cost a lot of money. I would go get a physical which should include blood work and an EKG. That would be the best place to start.
I'm in a situation where all my exorcising has to be done outside. During the cold days of winter I have little choice but to become a couch potato. When ever possible I'll do some bending exorcises such as bending over to touch my toes as many times as I can (20 or so times) and bending over and reaching for my ankles on the opposite side, (left hand reaching for the right ankle), doing this fast enough to get my heart pumping but not fast enough to shack the house. I also find an excuse to go upstairs at least twice a day. This is far less than I should be doing but under the conditions it's all I can do.
There are many video's on the market, I am not someone with an education in exorcising, anatomy, ect..but I would "assume" the best video's are those that get you moving... dancing and hopping around.... What was that guys name from the 70's and 80's that was all about exorcising?, I'm having a mental block with his name. He's still active and is still seen in TV commercials and in fact he was on Fox News recently. Any case, I would assume he's still pouring out the video's. I suggest him only because his exorcising is all about getting physical, moving around rapidly, ect.. as opposed to some of the others out there that do nothing but yoga type of stretching. Those are also good but with your suggested life style of sitting around doing nothing, activity is more important.
Another thing I do is purposely park the car as far away as possible at the super markets so that I have to "walk". I can only "assume" you still go out from time to time, When ever possible put your self in a position where you have to do "work" to get the job done.
Anything and everything you can do to get your heart rate up some, but not too much, and anything you can do to get the blood flowing through your arms and legs eating up those calories.
I live in the countryside and work on the computer. I'm a C# developer, plus a lot of other things, so I work and stress at the PC far to much. It's cold where I live ... very cold. We are miles away from any sort of gym. I'm to scared to start running on my own, because I have not exercised in a long time.
Maybe we can chat more. Help each other out sort of thing?
If you’re the type who surfs the Internet, chances are you could easily find exercise videos that way. One that I came through while I was browsing was Workouts on Demand http://www.workoutsondemand.com. You can try and see if this solution works for you.
Generally, I try to take a 15 minute break every 3 hours or so. That also helps with back problems and you get your blood flowing. I also take walks and have a skipping rope at hand when the weather's not that friendly.
And good luck on finding the right stuff that suits you.