External Hard disk Problem....Heeeeeeelp..!!?

I have a Toshiba 500GB external hard disk & have been using it for 4 months with my laptop, but after my desktop came from repair, the person who repaired it put kaspersky 6.0 antivirus on it.When i connected my harddisk to my pc, kaspersky blocked it from opening.Now when I connected it back to my laptop, it won't recognize a as a harddisk as it used to before , instead it says "Removable Disk D" & when i try to access it dosnt opn...it says "Please enter a Disk in Removable Disk D"....pleeeeease help...wat shod i do...???i hav lots of things on the hard disk wich i dnt wnt 2 loose....