You could delete what you put on it that do not want anymore from it, or moving them to another drive that does have free space. Do not delete the Recovery partition or the default files on it. This partition is what is used to recover Windows with.
If you do not plan on saving more to the drive and just wanted to stop the low disk space warning, then you could use METHOD TWO in the tutorial below to do so. However, I strongly recommend you to read the warning at the top of the tutorial below before doing it.
Your Recovery D partition is set up by your computer manufacturer in case of serious problems in your system.
You use that to restore your sytem.
You are NOT supposed to touch it.... not to add or remove anything to or from it.
If you have been using the recovery drive D : for files backup, or adding items into it, call you computer manufacturer, tell them the situation.......
1.Ask them how to remove the backup files or any items that are NOT supposed to be there.
They created the recovery partition, they know perfectly how to take care of it.
Let them teach you how to.
2. Worse comes to worst, ask them for a set of recovery discs and set your computer back to facgory settings.
If you have to do that, make sure you backup all files etc that you want to keep first before running the recovery discs.
3. Get an external hard drive for files backup. Never do it in your recovery partition.
