I hope I can help a little.
1. The computer itself is an operating system, so it won't just scan your entire computer contents. It would be able to do that for a USB stick, since there's no OS file that would stop it. Many OS systems block that ability, which is why the networking program is available. Some users have chosen to use high capacity thumbdrives or even USB HDDs, although not all of the HDD devices are supported.
2. Are the HD formats supported as listed in the manual? Most containers support specific video and audio codecs, and resolutions. I can't say why this would be happening if you're using a supported format, but if the format varies, that may be why.
3. This is listed in the manual as being not available as part of the DLNA and networking options. Some users have reported that it does work for some file types, but it's not officially supported on any file types.
Finally, if the network does seem slow, check to see what other devices you have on the network. If someone else is streaming YouTube videos while you're trying to watch an HD movie, that might also affect your network's ability to stream. Just a thought.
I bought a samsung LED 40" TV (ua40c5000qr) and the additional samsung wireless lan adapter. What an absolute pain to get it to work and documentation is minimal.
I have a few problems I can hopefully get resolved with your help.
1. WHen i connect to my laptop why can i not browse the directory structure on my laptop like i can if i use a usb stick. The TV seems to select a few directories and thats it you cant browse your computer. I installed pc manager (i randomly found out about) which kind of resolved the problem i was having. but was hoping to not have to install software to do this. "plug and Play" as it were.
2. This one is a big issue for me. HD video does not stream nicely. It stops every 30 seconds while it has to load the next 30 seconds. As you can understand this is very dissapointing.
3. You are unable to fast forward or rewind when watching a video wirelessly. Something you are able to do from a usb drive. when i try to is simply says "Not Available". very annoying
Hope you can help me resolve these else i might as well return the very expensive wireless device to samsung