Windows XP is the only version of Windowblinds that will skin the Windows Calculator. There are versions of different calculators on the internet that can be skinned by windowblinds. The best way to do this is search for "Windows Calculator" and pick one you like. Windowblinds will automatically pick up the buttons in most calc programs, but if not, try the settings in Windowblinds and make a specific rule to customize that particular program. If it still doesn't work. Go back to the drawing board and keep trying some programs until you find one that will skin. I use Calc-Add which can be found at:
http://home.att.net/~jdswanson/download/calcazip.exe
and the website is
http://home.att.net/~jdswanson/calcadd/ca-down.htm
Calc-add does cost $12.00 to register. But I think you will be happy with it's skinning capabilities. At least I am.