How can I deactivate iCloud to avoid "MobileMe Services Stopped Working" message?
Took me a few days, but found this:
http://support.apple.com/kb/HT2992
That worked for me
Uninstalling the MobileMe Control Panel for Windows 7 and Vista
To uninstall the Control Panel, follow these steps:

Click the Start Menu.
Choose Control Panel from the Start Menu.
In Control Panel, choose Uninstall a Program, which is under the Programs section (If you are using Classic view in Windows Vista, open the Programs and Features Control Panel).
In the Programs and Features Control Panel, under the listing of Programs, select the MobileMe Control Panel.
In Windows 7, click Change. Then, click Remove from the pop-up window. In Windows Vista, click Uninstall.
Follow the onscreen directions to remove the MobileMe Control Panel.

Uninstalling the MobileMe Control Panel for Windows XP
To uninstall the Control Panel, follow these steps:

Click the Start Menu.
Choose Control Panels from the Start Menu.
In Control Panel, choose Remove a Program.
If you use Windows XP, choose Add/Remove Programs.
In the Add/Remove Programs Control Panel, under the listing of Programs, select the MobileMe Control Panel.
Click Uninstall, and follow the onscreen directions to remove the MobileMe Control Panel.