try a system restore to the last known change maybe? often it`s some demo or badly written program messes up windoze, atm I have background task icons that won`t show up in the bottom right, some winderz stupidity I think, they are running in task manager, they are supposed to be visible according to the taskbar manager, but they aint, I guess M$ has broken something with a update of some sort, or maybe it`s some aspect of w!ndows being "helpful" without asking
[edit] NO! it isn`t the system tray cleanup tool before anyone mentions it, I have it turned off.
Windows: 32 bit extension/graphical shell for a 16bit patch to an 8bit OS originally coded for a 4bit CPU, written by a 2bit company that can't stand 1bit of competition, now available in 64bits.