It’s one of the most asked questions about Windows 7 and the answer is simple, absolutely not! There are few directories in the Windows 7 system root directory that you can delete without repercussion. All of the components in the operating system are found in the WinSxS folder. The WinSxS folder is the only location that the component is found on the system, all other instances of the files that you see on the system are “projected” by hard linking from the component store. An example of hard linking would be having a file called File1.exe (size 10MBs) located in C:\Windows\WinSxS. You can use a command in Windows 7 called mklink to create a hard link of File1.exe in say C:\Files. So when you look in C:\Files you will see File1.exe at a size of 10MBs but this is an “illusion” 😛 What you are seeing is a link to the file in C:\Windows\WinSxS. So File1.exe is not taking up 20MBs of disk space by being in two places, it is actually still only taking up 10MBs. So, although you may see files in various folders on your computer taking up diskspace they are really located just once in the WinSxS folder.
That explains why the folder starts off big, but not why it gets larger over time – the answer pretty simple. When a component is updated then new version is “projected” or hardlinked onto the system but the old version of the component is kept. So the more a component gets updated, the more previous versions there are of that component.
So to finish. Do not mess with the WinSxS folder 🙂