I came across this freeware app that replaces your existing Windows calculator over at The Red Ferret Journal.  Check out the functionality that this application has:

Adjustable calculator size – Make it any size you want and Moffsoft FreeCalc will remember the size and position next time you use it.

Tape – Save, print, or clear the simulated paper history tape.

Color schemes – Select a color combination or use your Windows color settings. 

New keys – Clear Tape {CT}, double zero {00}, triple zero {000}, and memory subtract {M-} keys have been added.

Visible memory value – You’ll always know what’s in memory because it’s displayed on the calculator status bar.

Option settings – Flat buttons, always on top, tray icon, run on startup, and hiding the tape are some of the calculator options. 

Digit groupings – Number groupings for easy to read numbers.

International support – Digit grouping and decimal point characters change based on your regional settings. 

Tray icon – Turn on the tray icon for quick and easy access. 

System requirements – Windows 95/98/Me/NT/2000/XP/Vista

Get your free copy from Moffsoft  here.