clicking noises? i heard that when mine was broken and kept disconnecting and reconnecting. Had to format it and get the data back thro some program (File Scavanger i believe it was)

Edit: buy a new one  I got one of 1TB for only 100€ and it works like a charm

Go for a bigger, newer (more reliable) one. Preferably Seagate. Make sure your backup the data (copy between your main machine and the ext hdd). Clicking dowsnt sound healthy, could be the read arms. Do you still have your old PC? Try plugging it in that and see if its readabale before you junk it...

Possible fix to get the data off would be to tap the drive on a hard surface, on its side. This may release any stuck read heads.

Absolute worst case, nothing can read it, stick it in a sealed plastic bag, pop it in the freezer for an hour, then take it out and try it. If you can get the data, copy it off as fast as you can, then junk it.