Is there a windows version of mac's garage band?

Audacity is NOT the windows version of Garage Band.

While both can record, Audacity is not designed to use loops to create music as is Garage Band.

The only free loop based app for Windows is Acid Xpress.

It's the free, lite version of Sony Acid Pro.

Function limited but able to create up to ten loop based tracks.

http://www.acidplanet.com/downloads/xpress/

Download free loops from the site and get more compatible free loops from Macloops:

http://www.macloops.com/ Sign up needed but no catches.

There are fairly some sturdy utility to apply for making song on a workstation. certainly one of my typical is FL studio. It helps many enormous and DXI plug ins and it is an exceedingly versatile software. additionally it comes at an exceedingly sturdy cost with each little thing you will desire to create exceedingly much any variety of song. Others comprise: Cubase, Nuendo,professional approaches, Magix sequoia, reason,Ableton stay, Sonar

check out audacity, a free audio editor

not as nice as garage band, but it's free and does a lot of similar stuff

you can also look at adobe's audition, but it's expensive