PS3 can't connect to media server problem?

Alright so heres the deal: About a week ago i set up my ps3 in my room, and then set it up to connect to my computer in order to stream media off it. At first things worked fine which was good but then all of a sudden my ps3 seemed to have 'lost' my 'My Videos' folder on my account - I worked around it by adding my external harddrive as a folder so my ps3 could just stream straight off that. Now, however, my ps3 seems to have misplaced that folder aswell.

Yes, I have restarted my computer.

Yes, I have restarted my ps3.

Yes, I can see other folders such as the 'shared videos' folder.

Yes, I have removed the 'missing' folders from the share list and re-added them.

Any ideas?

On a side note, all the while there have been a few files that my ps3 just doesnt seem to be able to see, which is really annoying.. They're the same format and size as a lot of files that it CAN see - not to mention in the same folder.. So yeah any help would be greatly appreciated.