External Hard drive corrupted

My Western Digital 150g external hard drive appears to be corrupted. It was working fine until out of nowhere the file names in the drive became hieroglyphics or like a wingdings font. The folders are there, however, if I click on them it says the file is corrupted and unreadable.

The drive is fairly new, it has everything on it, from pics, to music, to school work, etc.

Anybody out there know how/if I can fix it? I tried googling it but I cant find anything good.

you can do a data recovery. takes a while but if its imprtant then its worth it.

is this a 3.5 or 2.5 inch HD?