How can I ping a range of IP addresses simultaneously

Nmap is available for Windows:

# nmap -sP 10.0.10.1-100

The quickest way is to use Angry IP Scanner

I use it for the same way you want to!

I've used this command

for %%i in 200 to 254 do ping 10.1.1.%%i 

in a batch file for a similar reason