halogen ovens?

I Must add, these ovens are excellent when they work I have now had three in 9months, trying to replace the bulb which is readily available on ebay and other sources, is the easy bit trying to get them in the oven is a nightmare, I still cannot work out how, any answer in plain woman's language would be appreciated.I really don't think it is possible and in the end you buy a new one which will last another 3 months, ever had the feeling you are being conned.