thumbnail preview in Win& 64bit

[masque]

Ok, I've gone and upgraded to win7 64bit. I swore I wouldn't until it was at least 5 years old but I gave in.
However remarkably the only issue I seem to be having, once I'd changed my printer, my scanner, modem for faxes, digital tv tuner, sound card, motherboard,cpu and ram, is the almost complete absence of Xara Thumbnail previews. I say almost as I have two, one old file and one produced a few days ago.
I've read about copying' xarthumb64.dll' to the root directory and registering etc, all very interesting, but it doesn't seem to work. I'm not sure why I need to copy it anywhere as just right clicking and selecting register would seem adequate, though that doesn't work either.
Instead I get the attached, which seems to be a mixture of Chinese and English that might as well be chinese. I tried the age old solution of removing and re-installing Designer but that just used up half an hour and left everything exactly the same. Has anyone any ideas how I can get thumbnails back because if I have to rely on remembering what daft name I gave a file, given that I have hundreds and hundreds I'll never find anything again.
Derek