Adb.exe is missing. (Windows 7)

After restarting the computer when the Android SDK have been installed Eclipse can start with an error message telling that the adb.exe is not found.
I found out that Windows itself must do something to the installed files because they are not found in the installation directory after restart. It seems like Windows 7 remove some files that the SDK relies on. The file "adb.exe" is removed and you nead to install the whole package again.
 I also found out that the file path in my case "C:\Program Files (x86)\Android" was set to "read only" so when i tried to install the SDK again, it didn't work before i removed the "read only" attribute.

After installing the Android SDK the installed Eclipse works again.