Which "weeds" do you have in that bed? If they are like the wild Phlox and spread by roots, as well as seed, then the best way to fix that bed is to dig it up and pull those roots out.

I am somewhat handicapped and have had 2 knee surgeires so digging is not my ideal job. I was thinking of spraying,putting cardboard down and mulch on top Do you think that would work. Thanks for your help. I may attempt the digging a little at a time. My son works and has his own family so it is hard sometime to get him.

Depending on which "weed" you have and need to control there may be no need to spray anything first since covering many plants with newspaper or cardboard blocks that plants access to the sunlight all plants need to grow and if the sunlight is blocked the plant will die.
Some invasives, such as Quack Grass are not necesarily done in that way, however, since the rhizomes store large amounts of nutrients that let them grow for quite long periods of time.