Is there a way to run Windows without installing it?

Yes, HirenBoot has the "Mini Windows XP" feature.

Portable Windows Xp that runs from CD/USB/Ram Drive to repair/recover dead windows operating system. It has LAN and WLAN (Wireless) Network includes 300 WiFi/Ethernet card drivers and can also be customized easily to add your own drivers in HBCD\Drivers folder.

UBCD4Win is what you're looking for. Runs a copy of XP from a CD ROM