Hi hebert55 - Welcome to w7forums
Have you tried installing your programs with UAC turned off?
Read more here -
Configure Windows 7 UAC
Also have you tried what Kalario mentioned?
Read more here -
Application Compatibility Mode
If you was only having troubles with one or two apps I might would think this was normal. But as you are making it sound as if you have many apps something has got to be blocking them from running that they are not programmed to deal with. I would say that the UAC is the biggest cause to programs not installing or running. This maybe great in the future but for now when installing older programs its best if disabled and once the apps are installed you can turn UAC back on and see if the apps will at least run with it turned on. I myself leave UAC turned off.