HP stores their recovery partition on the D partition, on the main drive of the computer. System Restore points for the C: drive are generally NOT stored on the D: drive, but instead are stored in the System Information files on the C: drive.. You do NOT need to perform anything on that particular partition and it should not be tampered with UNLESS you want to remove everything from the partition and use it as additional free space after the removal of the recovery files.. IF your remove everything from the Recovery partition, you will not be able to use it to perform a full factory recovery.. As such, if you decide to remove files from the D: drive, BE SURE to have a good, working copy on Recovery Discs.
Hope this helps.
Grif