Hi,
1. Since when are you facing this issue?
2. Do you recall any changes made to the computer prior to the issue?
Method 1: ****
a) Right click the Desktop.
b) Select View click on Show Desktop Icon.
c) Make sure the option is checked.
Method 2:
Step 1: ****I would suggest you to start the computer in safe mode with networking and check if the issue persists, for more information refers to the link mentioned below:
Advanced startup options.http://windows.microsoft.com/en-US/windows7/Advanced-startup-options-including-safe-mode
If the issue does not occur in safemode with networking, you may configure the computer into clean boot and check if the issue persists. It will start Windows7 by using a minimal set of drivers and startup programs and helps to eliminate software conflicts.
Step 2: How to troubleshoot a problem by performing a clean boot in Windows Vista or in Windows7?http://support.microsoft.com/kb/929135
Note: Refer step7 from the above link to set computer to start as usual after the troubleshooting is performed.
Method 3: ****You may run a complete PC virus scan to check if it is infected by viruses. Refer the following link to do the same:
http://windows.microsoft.com/en-US/windows/products/security-essentials
Method 4: ****You may update the display adapter by visiting the manufacturer’s website and check if it fixes the issue. Refer to the following link to do the same:
http://windows.microsoft.com/en-us/windows7/Update-a-driver-for-hardware-that-isnt-working-properly
Hope this helps.