You uninstall most software via the "Add or Remove Programs" applet in
Control Panel. To re-install them to another drive you will need to have the
original install Cds or installation package, the data should be unaffected
but if in doubt back up your data to CDs or an external drive, you will have
to reinstall any updates or sevice patches once the original software has
been re-installed.

Some times by selecting to do a custom install you will be asked where you
want the software installed to, other times just changing the drive letter
(eg C:\) to the letter of the drive to which you wish to install the
software will suffice.

Another area you may be able to pick up space is from the Windows directory,
go to Windows Explorer, click on Tools and then Folder Options and then the
View tab, make sure the radio button for "Show hidden files and folders" is
selected, then click on "Apply to All Folders", then click on OK. In the
windows directory you should now see a number of blue coloured files
starting with "$NTUninstallKB" and followed by a number of numbers, these
are the uninstall files for various windows updates, if you machine is
running fine and you do not believe you will need to uninstall the patches
you can safely delete them, this can recove a vast amount of space.