Yes, Mary, you certainly can substitute dried herbs for fresh, and vice versa. This will bring out their oil and enhance their flavor. If you are using dried herbs in a salad, steep them in a little hot water for a minute or two to make them more aromatic and tender. When I make roast beef, I season the outside of the meat. After it is cooked, I never taste the seasoning on the inside.
Rubs work the best for oven-roasted meats.
Even though the inside won't taste as seasoned as the outside, rubs do a better job of giving overall flavor than simply seasoning the meat before you slide it into the oven. Let the rub work on the meat for at least six to eight hours prior to cooking, and leaving it on overnight is even better. The following is one of my favorite rub recipes. Give it a try, and when your family raves about your roast, you can brag about your new technique. Just don't rub it in.