If I have screen recording videos containing text that I want to blur or censor out, how can I do that in Windows 7?
The answer to your question is that it is not possible to blur footage with the default set of Windows 7 apps. 'Windows Movie Maker' used to be the go to free software for basic editing but it's now only downloadable from Microsoft and isn't actually 'free' for all intensive purposes.
Your solution is here:
Download 'Shotcut' video editor for free here.
Follow the instructional video on how to blur parts of an image using Shotcut Here
It does not matter, that you are running Windows 7.
What you need is a video editing program.
For blurring, pixellation and basic censoring, you do not necessarily need expensive software such as Sony Vegas.
Free software such as OpenShot (originally for Linux, but also available for Windows) could also do your job.
Alternatviely, you can download and burn a DVD with Ubuntu Studio, and boot from that DVD. Some video editing software, including KDEnlive is pre-installed out of the box.