Hi full, welcome to NST.
Which partition is marked "system" in Disk Management ?
I'm not sure of the Italian translation. It's not in our translation
database yet.
Perhaps you could update it when you have a moment after we've sorted your problem.
If W7 is "system" and "active", then you can just format the XP partition after saving your user data and use EasyBCD to delete the entry for XP from W7's BCD.
If XP is "system" and "active", then that's where W7 has put its boot files, so you'll need to be a bit more careful removing XP.
If you get yourself a
live copy of Linux, burn it to a CD and boot it directly from the CD without installing it, you can use it to delete everything on the XP partition
except your user files , bootmgr, and the folder named boot. Then use EasybCD (add/remove entries) to delete the XP choice from the W7 boot menu.