My DK03 keyboard which has been working perfectly for years is not behaving. 

Keys are not responding properly.  I went to the key test website and am seeing weird behavior on specific keys.

For example, "E" key is now doing a key combination of  "+", "R" and "E".  The enter key is not working at all etc...

It's like this for many keys now.

what do I need to do to fix this?

Regards