How can I fix my Kenwood HD50 Hair Dryer from overheating?

I have a Kenwood HD50 hair dryer and I've been using it for 7 years. It worked all these years without a single problem . Recently it started overheating and losing power within two minutes. It has not shut down completely yet because I switched it off every time it overheated because I was afraid it would go out completely and never operate again. Even though I left it off (sometimes for several days ) and I unplugged it during that time, when I tried to use it after some days the same thing happened ( overheated so much that within 10 seconds the heating system inside started glowing with a bright orange color from the heat and became very weak in blowing force) . Now it is practically unusable although it has not shut down completely yet. I want to fix it because it is the only hair dryer that was good for my hair.

How can I fix it ? Do I replace the heating system ? Are there spare heating system parts for that ?

( Also , I called Kenwood customer support and they told me it is so old because kenwood doesn't release hair dryers for several years now. But they couldn't even tell me when it was released or if there are any same models left in stock somewhere. Also I can't find anything about it from google. How is that possible? Doesn't Kenwood keep a file/registry of all the models they have ever produced? )