Yes, there are many solutions to this. Take a look at VirtualBox (which is the one I've tried and which works for me). It's available for Windows and Linux, allowing you to run either in the other. It's easy to set up in windows, and there's good documentation on their website, which I suggest you read before starting!
www.virtualbox.org
I'm not sure if all your peripherals will work though (such as your printer). Might be worth considering VMWare Player/Server for that, although I'm not sure if they will manager it either.
edit: as to whether it's better to have windows running in slackware, or the other way around, well that depends largely on which one you use the most. If you use slackware the most, then install VirtualBox in slack, and install windows in a virtual machine. You'll probably find that you get better performance from the virtual machine when it's running from within slackware due to slack's generally lighter memory footprint. I run windows in slackware, and it's almost native speed.