Software Deployment

hi
when i try to install a program sometimes ill get a prompt saying your trying to access
a problem that is not available.then it asks 4 a cd which i dont have so i cant install the
program.anything i can do about it??microsoft has a windows installer clean up.should i
try this?it waas suggested that i should uninstall windows xp and lose my data and rei-
nstall it but im not comfortable with this.any ideas?thanks

benbernie