Are there any booting issues or strange noises? So, you see all the icons but you are missing the start menu and the taskbar right? Trying to access the Task Manager was a good idea because this way you can really solve the issue. However, if it is not accessible, try booting in Safe Mode. Any changes? If no, use a Windows installation drive and select the Repair option. This way you may be able to fix some booting problems without harming the stored data. I believe you are facing a software issue, so the stored information should be safe.
If you manage to boot normally, backup all important data and update your anti virus software. Do a complete system check.
Hope this helps