Vista Home Premium Problems

Hi I,m running same type of computer with similar problem only just recently started doing this but it is a real pain. whille trying to open some programs but mainly windows mail or firefox & 2 out of 3 times the program starts to open then disappears. I have found that by trying again a message saying that this program is already running appears but i cant find it. So I log out & reopen windows & bingo while shutting down what appears in the background the hidden program. How can I overcome this as it is very painful any help would be greatly appreciated:wave: