Dear Sawsan,
Sure you don't want to open a new thread? This thread is on a different topic! Anyway,
did you open any e-mail attachments just before this happened? E-mail attachments are notorious for malware entry! Run an Online Anti-virus scan, for ex. Trend Micro's Housecall. Link http://housecall.trendmicro.com/ . If Malware is found, kindly click on "report" at the right bottom corner of the reply box and request the moderator to move your post to the Malware and HJT forum!
PS: fighting4focus may get angry at you, Sawsan!