Just to prevent you worrying, all the files on your desktop are safe! They can still be accessed: C:\Users\*Your account name*\Desktop\ (If you are using Windows Vista or 7)
Save any documents you have open before proceeding
To view them on the desktop, press the Windows key+R and type 'taskmgr' into the run box, click the processes tab at the top and find 'explorer.exe', click it once then click End Process at the bottom, at this point your task bar will also disappear but no worry, click file, then run, then type 'explorer' into the box, then press enter, at which point everything should return to normal!