Alright, I've noticed a pattern in the Win10 related threads. Since a lot of people on GAF never upgraded past Win7 they are either entirely unfamiliar with the process for upgrading Windows or only experienced the XP -> Vista -> Seven upgrade path, which was quite traumatic and required a lot of work to get everything running. This thread is intended to clear up the doubts.
Starting with Windows Vista, Microsoft got their act together and created an in-place upgrade system that is relatively painless. It's done entirely inside the OS, there's no need for ISOs or USB drivers. You run a small program, it downloads everything in the background and when it's done it guides you through the process, which requires minimal user input.
The new upgrade process preserves all your programs (with a few exceptions, more about that later), files and settings, down to the position of your desktop icons. When the upgrade is done, your PC is ready to use. IT is also possible to "undo" the upgrade entirely (as long as you have sufficient HDD space). The old OS is backed up as it was before the install.
Usually, any programs that embed themselves too deeply into the system like anti-virus or programs that rely on virtual drivers like VMWare require some extra steps like repairing the installation, but the upgrade process will detect them and guide you through it.
Ah, this upgrade process is very unlikely to "bloat up" your Windows install. Performance won't be that much different than if you did a fresh install and installed all the programs you currently use. Trivia: you can actually use this upgrade system to repair your Windows 7 install, by "upgrading" it to itself. It fixes corrupted system files, bad/corrupted driver installs, messed up registry and a whole lot if problems as only a few specific branches of the registry are migrated over to keep installed programs working. This is how the "refresh my PC" feature of Windows 8 actually works under the hood.
Of course, if you want to take the opportunity to get a "fresh start", it should be possible. The situation with Windows 10 in that regard is still unknown (whether you can use your CD-Key to install from an ISO or not), but you should be able to clean up your system after you upgrade by using the refresh/reset features introduced with Windows 8, where you can reformat the system from within Windows without need for DVDs or USB drivers.
Finally, even if you don't want want to upgrade right now because reasons, you should reserve your Windows 10 upgrade so you have the option to upgrade later for free.
-- EDIT --
Want to try Windows 10 without messing with you PC? Download the tech preview ISO and install it on a virtual machine using the free VMWare Player.
Nope. I have several developer tools installed and they all worked after update, even stuff like TortoiseSVN and TortoiseGIT, python, chocolatey and etc.
Nope, I have FFDshow and DivX installed and it remained working after upgrade.
My Unity 5 install survived the process intact.
Again, the only kind of programs that can be "broken" by the upgrade are ones that hook into pre-boot (anti-virus and anti-malware software) and those that rely on custom drivers or virtualization features (VMWare). Video codecs, shell extensions (TortoiseSVN, etc), browser plugins, IDEs (Visual Studio, Eclipse, etc), cygwin, python, etc, all work as usual.
Starting with Windows Vista, Microsoft got their act together and created an in-place upgrade system that is relatively painless. It's done entirely inside the OS, there's no need for ISOs or USB drivers. You run a small program, it downloads everything in the background and when it's done it guides you through the process, which requires minimal user input.
The new upgrade process preserves all your programs (with a few exceptions, more about that later), files and settings, down to the position of your desktop icons. When the upgrade is done, your PC is ready to use. IT is also possible to "undo" the upgrade entirely (as long as you have sufficient HDD space). The old OS is backed up as it was before the install.
Usually, any programs that embed themselves too deeply into the system like anti-virus or programs that rely on virtual drivers like VMWare require some extra steps like repairing the installation, but the upgrade process will detect them and guide you through it.
Ah, this upgrade process is very unlikely to "bloat up" your Windows install. Performance won't be that much different than if you did a fresh install and installed all the programs you currently use. Trivia: you can actually use this upgrade system to repair your Windows 7 install, by "upgrading" it to itself. It fixes corrupted system files, bad/corrupted driver installs, messed up registry and a whole lot if problems as only a few specific branches of the registry are migrated over to keep installed programs working. This is how the "refresh my PC" feature of Windows 8 actually works under the hood.
Of course, if you want to take the opportunity to get a "fresh start", it should be possible. The situation with Windows 10 in that regard is still unknown (whether you can use your CD-Key to install from an ISO or not), but you should be able to clean up your system after you upgrade by using the refresh/reset features introduced with Windows 8, where you can reformat the system from within Windows without need for DVDs or USB drivers.
Finally, even if you don't want want to upgrade right now because reasons, you should reserve your Windows 10 upgrade so you have the option to upgrade later for free.
-- EDIT --
Want to try Windows 10 without messing with you PC? Download the tech preview ISO and install it on a virtual machine using the free VMWare Player.
Nope. I have several developer tools installed and they all worked after update, even stuff like TortoiseSVN and TortoiseGIT, python, chocolatey and etc.
Nope, I have FFDshow and DivX installed and it remained working after upgrade.
My Unity 5 install survived the process intact.
Again, the only kind of programs that can be "broken" by the upgrade are ones that hook into pre-boot (anti-virus and anti-malware software) and those that rely on custom drivers or virtualization features (VMWare). Video codecs, shell extensions (TortoiseSVN, etc), browser plugins, IDEs (Visual Studio, Eclipse, etc), cygwin, python, etc, all work as usual.
.
