Windows 7: network locations disappear

Hi guys,
i have a problem with my home network, the setup include two windows 7 ultimate X64 connected by router. I've created home group to include these computers.
here's a description of the problems:

1.after a power failure, when i open a network location some of the folders in that locations are visible but after a while the same folders disappear, after a while the files become visible again.
i run SMART scanning software for my HDD but no errors was found.
the problem accrued on one of the computers with 1.5 TB HD.

2. this problem already existed before the power failure. windows media center wont let me add files to library from network location. when adding the files, media center seems like adding it but the files wont appear in media library.

i came here after spending tones of time in order to find the solution i tried everything but the problems still there.



does any one have a hint?
Thanks