hi !
do u use a download manager ? if yes, which one ?
rt click on ur bar and see the task manager. do u c any uknown processess ?
maybe, just maybe your system has been infected.
so why dont u run ur anti=virus (avast/avg/etc) and ur anti-spyware (ms anti-spy and adaware). ideally schedule their boot-time scan or run them in safe-mode. also clean up ur pc junk. use ccleaner.
