If you are looking for classic functionality without installing a 2.0 version, consider:
: Unknown publisher. Fix : Click “More info” → “Run anyway”. oldclassiccalc-2.0-setup.exe
and decide if the app is for just you or all users on the PC. and wait a few seconds for the magic to happen. Step 4: The Final Touch If you are looking for classic functionality without
: Replaces the modern app with the familiar Windows 7 appearance, including standard, scientific, programmer, and statistics modes. oldclassiccalc-2.0-setup.exe
Scan the file using VirusTotal before execution to check for trojans or adware.