Almost all Unix/Linux systems use the 'df' command to find out how big the partition is, how much is in use, and the percentage of the system in use. This command must be used in a command window.
disk space analyzer
GNOME Disk Usage Analyzer
I'm not sure what you are referring to by "disk management." There are many utilities to check disk usage, delete files, and manage space quotas.
You will have less disk space available for OSes.
Check if your floppy disk has turned into a hard drive
Defrag
Ubuntu uses the ext4 file journaling system, which doesn't get fragmented.
Yes, it can be done from the windows installation disk, but it's cleaner if you remove ubuntu with the ubuntu live cd and then install windows.
df df - report file system disk space usage du du - estimate file space usage
Check that if your computer is affected by worm
edquota -u username
No. After download and burn the Ubuntu 10.10 install disk, you can either TRY Ubuntu without affecting your Windows at all, or INSTALL Ubuntu to have them both in your PC. However, to install Ubuntu, you need to be careful. Make sure not to install Ubuntu to the Windows drive. That is all.