2 partitions on my external 120gb HD have become inaccessible. Their names now appear to be "Local Disk", and if you try to access them you get an error message.

http://www.imageviper.com/displayimage/11865/0/s.JPG

The drives F and H in the picture above are the ones having the problem. Drives G and I are behaving as they should.
I have had a couple similar problems in the past, but those were solved relatively easily, whereas this I can do nothing for. This problem varies a bit every time I restart the HD -- Sometimes only one partition is having a problem, and some times apparently no partition is having a problem, but the hd still acts really slow and buggy.

Please help me :D

Does anyone have any help? :(

Sounds like the hard drive may be failing - check out the manufacturers website - they may have a testing util. If the drive comes on occasionally try to run the test on this drive and get it sent off for repair or replacement(if still under warranty) if & when found faulty.

How does the drive connect? Is there any problem with the sockets or cable?