Excel file format problem

[*BADAL*]

salam friends,
aaj meray sath aik problem hua hay woh yay kay meray excel kay kuch files tay to aaj jab may usay open kar raha ta to yay probelem arha hay.meray khyal may yay kisi virus kay waja say hua hay.kiynakay jab may nay KAV say apnay pc ko scan kia to buhut virus detect huay jinhay may nay delete kia likin ab masala yay hogaya kay buhut say programmes including office kay icon he change hogaye aur ab jab may open karta ho to koi be programme open nahi ho raha hay.to plz help me.especially how to open these excel files.shukria