Ran SyncToy to sync
F:. Before I stopped it, SyncToy managed to copy $RECYCLE.BIN from
E:, which is gigantic. I emptied my Recycle Bin but
F:'s didn't delete. Haw can I manually delete it?
You can use an Ubuntu live-cd for this. It will automatically mount your NTFS partitions when it boots, and you can directly delete the folder through the file manager, under Places>Computer.
If you try this and there is a problem "deleting" the folder, it may be due to a lack of system memory. This could occur because the session is running "live", so Ubuntu will try to maintain it's own recycling bin by default... in memory. If this happens, you can enable a "direct delete" option in the file manager's preferences settings.
You might have to take ownership of the files in order to do an explorer based delete. However, if it is huge, changing all the ACLs could take a long time. It would be faster just to quick format the drive.