I have multiple installs of Gentoo.
One which I like to call my "regular" install plus 2 for experiments that might break things.
Over the last two years my regular has accumulated a lot of cruft.
The Gentoo package manager uses configuration files which makes for a very flexible system.
You can mix stable with unstable,change dependencies prevent certain packages from installing etc.
By having /home on a separate partition you can (with some trickery) replace all your software
and config files and continue like before with a cruftfree system.
All your /home files will stay untouched like mailbox bookmarks pictures etc.
To do this I made backups of every partition involved on a USB disk,in case of disaster nothing is lost.
Tomorrow I'll fire up my copy of rescuecd and first reformat the partition where the software is located.
Then I'll copy the new system on it.I 'm typing this from the new sytem.
What is left then is make sure ownership and privileges are in order.

I have very little experience with Windows but I wonder if something like this can be done in Windows.
Gerard.

Wow, you sure are brave Gerard. How long have you been using Linux to know how to do that. I am going to stay at being a dummy, it is safer.

More than ten years I think.
I was using Windows 98SE and wasn't happy with it.
I read in a Dutch computer magazine a post from a subscriber how Linux was much better.
That's how I got started.
In those days you had to buy a cd to install Linux.
Did a lot of "distro hopping" until I found Gentoo in December 2003.
Never looked back.
It's a lot harder and takes a lot more time to install than binary distro's but it gives you complete control.
And it only installs what you want,not what the distro people think you need.
Gerard.

These are the benefits of using a well-organized system such as GNU/Linux.
I in my early years with GNU/Linux I did my installations with /home on separate partition. Since the LiveCD are common and very accessible, I did not even put my /home on a separate partition. If I have a problem with Kubuntu I solve it from a LiveCD with "chroot". If I need a clean system installation, first make a backup of /home, install the system with the same user name and restore the /home from backup with a LiveCD.
Surely you can not do this in Windows, for things like the rat's nest that is the disorganized Windows registry.

I don't think your procedure can be done on windows although it is possible to back up the registry. A good uninstaller to monitor installations is a wise investment.

The only way I know is the same for both windows or for linux

I keep the operating system on a small partition.
my XPsp3 is 8GB, Linux root is 15GB, linux home is 10 GB

All data (images/documents/video/audio) stored on the remainder of the disk(s)

I make regular partition images of C: and root and home using an Acronis TrueImage live booting usb. (used to use a live CD). Since the OS partitions are so small a backup / restore is a matter of minutes. These days I back up to a USB hdd

Any problems and I restore the last image. If I want a really clean version I revert to an early image.

Been doing it this way for years. Originally used Norton Ghost booting off a 3.5 floppy but have to admit that was hard work.

Well housecleaning finished and working.
One little hitch,for some mysterious reason I had to refresh my user password.
Glad I took the step,now a much leaner system.
/ went from ~30G to ~11G.
Gerard.

Good clean!

"filelight" is very useful to detect things that are taking up too much disk space.

Heck all i had to do was turn my PC on last week and Windows succeeded in house cleaning me right quickly.
So you can clean house in Windows very easily just keep using it.Eventually it will clean your house too.

Although Windows keeps your files for you.If you want them back you have to do some crazy rain dance or zombie witch doctor magic.I am not sure of which as i haven't gotten mine back yet.

Oh well only 140 gigs of stuff gone...poof THANKS WINDOWS!

Sorry about the rant...just seemed a great place to put this when you mentioned house cleaning in windows.

Well I guess that's what you get from systems built by people only interested in making oodles of money.
But being very poor programmers.
Linux/Unix was built by real professionals from the start.
Gerard.

Well I don't know about that... when Linus wrote the first version of the Linux kernel, he wasn't exactly a professional - although he's certainly become one since then. Linus himself has said the code he wrote on the first versions of Linux was horrible.

But I don't think it's necessarily a bad thing - many of the best innovations have been made by people who were not "professionals", but enthusiastic hobbyists who found a need and figured out a good way to fill that need. Some of the best coders of my generation were people who started by playing around with C-64:s, writing code and hacking things just "to see if they could"...

I beg to differ dd.
http://en.wikipedia.org/wiki/Bill_Gates
Unix existed long before MSDOS.
Gates never finished university Linus did.
Gerard.