what can i do ..i scan it already and when i turn on my pc it always appears in my desktop

Well my first approach would be the good ol' anti-virus/spyware program but I can see that didn't work in your favor. The next thing I would suggest is a feature called system restore. What it does is give you the opportunity to restore your computer to a certain time in the past, a time of your choosing. You would access the feature and restore your computer to a point before you received this virus. These are the steps you need to take:

Go to "Start"-"All Programs"-"Accessories"-"System Tools"-System Restore." Once here just follow the simple on screen instructions to bringing the computer back.

Hope this helps. Good luck and have a great day.

System restore is always a good thing to do. If you can't try and boot into safe mode and manually delete it.

Get a mac. NO VIRUS's!!! mac=no virus. its as simple as that