Based on what I read, yes it'll. You'll have to copy your data somewhere before install and reinstall all application afterwards.

Sergey, where are you getting your information?

You don't "lose" your data...even in a complete install (i.e. no "upgrade"), the Windows 7 install will create a folder.....such as c:\windows.old.001.....and anything like SQL Server databases will be installed inside....

For instance, I have a folder on a Windows 7 machine... C:\WINDOWS.OLD.001\PROGRAM FILES\MICROSOFT SQL SERVER\MSSQL.1\ and then several MDF files.

Items in your previous USERS folder are saved out under C:\WINDOWS.OLD\users as well.

Now, "should" someone back up their machine first? Of course.....but a normal install will move previous databases (basically, anything under program files) and previous USER files to something like c:\windows.old