thank you BossDweebe for your fast answer. Yes I mean that!
In general terms I mean "link on the desktop pointed to external resources" like:
link to removabke USB pen
link to memory card
link to network computer
link to network shared folder [not on my PC].
My idea was that windows clean periodically broken (or not apparently working) link from the Desktop:
Probably I found the solution to solve this issue:
First click on Start Menu > then Control Panel > go to System and Security > Administrative Tools (near bottom) > Task Scheduler > Task Scheduler (Local) (upper left) > Task Scheduler Library > Microsoft > Windows > Diagnosis >
(right pane) Right click on Scheduled > Disabled
If this is enabled then all desktop shortcuts to external drives like card readers, usb drives, CD/DVD drive and also control panel items as well will be deleted by Windows 7 when planned