With 30 gigabytes for Win 7 to reach rather, it depends on how many other programs you must install on the boot disk partition or want.  I would say :50GB

To find, open or start run the Windows-7 on screen Keyboard please use one of these Solutions

To open start, run, find the Disk-Management in Windows 7 There are several ways to open the Disk-Management in Windows 7. Here are 4 methods to open the

If you have problems with Aero in Windows 7, to fix and activate it, please start the "Find and fix Aero Problems" in Win-7. Image-1 Find and fix Aero Problems