ENGLISH:
When one of your disks gets low on space, Windows warns you and suggests you to run the Disk cleanup utility.
If you want to disable the warning, open the Registry Editor (Start->Run, type regedit) then navigate to
HKEY_CURRENT_USER
-Software
--Microsoft
---Windows
----CurrentVersion
-----Policies
------Explorer
If you are missing the Explorer folder, simply create it by right clicking on Policies and selecting New->Key
Now check for the NoLowDiskSpaceChecks entry. If it’s not already there, create it via Edit->New->DWORD then double click it and set its value to 1.