On Microsoft Windows Forums > Windows 7 Forums > Performance and Maintenance  a question was asked: power icon from the task bar is missing.

http://social.answers.microsoft.com/Forums/en-US/w7performance/thread/e7f180ef-81e3-40da-8703-64aced7383c7 

The answer states that Check boxes may be disabled and greyed out probably due to third party drivers that want to show manufacturer's icon instead.

They suggest you go to http://support.microsoft.com/kb/945011 Most Microsoft articles get moved on a daily schedule to prevent anyone finding an answer, but with a little luck you might find it.

Power Options are usually meant only for laptops, where you want to save battery power.

You can find some options in the Control Panel, but most are not available because you don't need them.

Surely a desktop should have all the software options of a laptop, even if they aren't particularly needed? I find that even on my desktop, I am missing Windows Mobility Centre and the ability to quickly change power options. 

Anyway, thanks for the answers, I'll guess I'll just have to do it the manual way from now on.

Desktops usually do not have the hardware connections needed to support all the possible power configurations of a laptop. I (and many others) have had mucho problems trying to run even sleep and hibernate smoothly  on desktops, This not just with Dell but other brands. Most functions are designed to reduce power drain during battery operation. You still have screen shut off and sleep mode/

I hope I can revive this thread so late after the last post - I am in the same situation.

I use my XPS 8100 Desktop (W7-64) to run audio production software and want to be able to switch to my "Disks On" power profile without having to go into the Control Panel.  I used to be able to do this on my old XP machine via the Power icon in the system tray but on this one the option to enable it is greyed out.

I have also discovered that this may have been disabled by the manufacturer and I have read the above discussion.  I understand the argument that power-saving options are not as important to desktop users but we also get electricity bills!  I want to normally run under the Dell default setting but change to "Disks On" when needed. 

Can someone confirm whether this is a Dell setting and describe how to undo it?

Thanks and regards,
Swatcher

Swatcher - I'm yet to try this solution, but others on the Microsoft forum have verified it worked for them. It's been a long time since this thread was started so you may have fixed the issue already.

http://answers.microsoft.com/en-us/windows/forum/windows_7-performance/power-icon-from-the-task-bar-is-missing/e7f180ef-81e3-40da-8703-64aced7383c7

Please perform the following steps:

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
 

1. Click  Start.
   In the  Start Search field, type  regedit.exe and then press Enter.
   If you are prompted for an administrator password or for confirmation, type the password, or clickAllow.
2. Locate and then click the following registry subkey:
   HKEY_CURRENT_USER\Software\Classes\Local Settings\Software\Microsoft\Windows\CurrentVersion\TrayNotify
3. In the Details pane, click the IconStreams registry entry.
4. On the Edit menu, click Delete, and then click Yes.
5. In the Details pane, click the PastIconsStream registry entry.
6. On the Edit menu, click Delete, and then click Yes.
7. Exit Registry Editor.
8. Restart the Explorer.exe process. To do these, follow these steps:
   1. Press CTRL+SHIFT+ESC.
   2. On the Processes tab in Task Manager, click the explorer.exe process, and then clickEnd Process two times.
   3. On the File menu, click New Tasks (Run), type explorer, and then click OK.
   4. Exit Task Manager.
9. Once Explorer.exe has restarted, right click on the clock and choose "Customize Notification Icons".
10. Ensure that Power is set to "Show icon and notifications".
11. Click on "Turn system icons on or off"
12. Ensure that Power is set to "On".
13. Click on OK and close the Control Panel.

Hope that helps, have a great day!

I have stuck with the same problem: one day power icon just disappeared from tray and no one solution worked. Luckily, with time I have found a solution. In Windows registry check the “HideSCAPower” parameter in two paths:

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Explorer

They both must be either does not exist or set to zero values.

In my case they both existed, but the last one was set to one. Most probably it was set during installation of any software, but I dunno... it is an old diagnostic laptop with a ton of strange vendors' software.