Network Failed

Hello: I wrote earlier bout this but have better details now.
If I download updates I loose items in my shared folders. Not really but
they are no longer accessable. The folder is still shared however.

My proxy lets me use the internet but the files can not be shared. If I
crash my machine a couple of times copy the files in the shared folder to my
desktop empty the folder then move the ones on the desktop back in it works
again.

Anyone else seen this?

Thanks