Right click on My Documents on the desktop.... select Properties and then
"Move" and move to the D: drive.
For anything else you'll have to use Add/Remove in the Control Panel and
uninstall the program then reinstall using the Custom option and direct it
to install most of it on the D: drive. Remember the Registry is still going
to be on the C: drive and data will be installed to that no matter what you
do.
Also run a Disk Cleanup.... and if things are working fine, remember to
remove the System Restore files as well. This should at least give you some
space to work with.
The only way to combine partitions without losing data is to use a third
party software like Partition Magic.
