Hi Michael,
Saw your post on the other thread. Do you have an ED nurse? If not, who prescribes your tablets? And you say you have tried all the tablets but which ones - I imagine you have had Viagra and Cialis but have you tried Levitra yet?
Sadly, the tablets don't work for everyone so you may need to ask your ED nurse or GP to prescribe Caverject injections or muse (which comes as pellets or cream). If you go down the injection route, the nurse should show you how to use it before you are let loose!
If the erection doesn't last very long with the pump you are either not using a tight enough ring or not getting a good seal before you slide the ring from the tube to your penis - do you trim your pubic hair and use plenty of KY jelly where the tube meets your skin? If the next size ring is too tight, try a combination of rings - many find that 2 rings works better than one.