XP to Win7, Media streaming over LAN freezes

The other day, I upgraded my file storage system from XP Pro to Windows 7 Ultimate 32-bit with a totally clean install. For 3 years this system has been on XP and has streamed media (.avi, .mkv, .mpg, most everything) over the LAN to my other home computers without issue. Ever since I installed Win7, media coming from a 1.5 TB hard drive on a Rosewill RC-212 RAID card skips, freezes, and sometimes completely closes on me when I am watching it on my main system which runs Win7 Ultimate 64-bit. If I stream the same media from a SATA HDD on the motherboard's SATA ports or from an IDE hard drive, it works fine over the network. I have tried installing new Vista 32-bit drivers from Rosewill for the RAID card but I get an error from the setup which states:

"Sorry, the install wizard can't find the proper component for the current platform. Please press OK to terminate the install wizard."

I tried getting drivers straight from VIA for this card and while those installed, the problem persists. Rosewill tech support was more than useless, stating Win7's drivers for the card are adequate enough. Going through Device Manager, I uninstalled the generic driver the OS provided the card and tried getting it to use the downloaded driver. It refused and chose to reinstall the generic driver.

I have also tried hooking up the hard drive to another SATA port (taking it away from the RAID array), turning off IPv6, making sure everything in the OS was updated fully, and checking any firewall issues (there are none). Still this problem continues.

I use WinAmp and/or Media Player Classic to watch the media. Things are a lot worse if I am using WinAmp but both players will freeze at random points. I also use Remote Desktop to manage this storage system, and whenever the media freezes, Remote Desktop does as well and has to reconnect. If anyone is wondering why I didn't just stick with XP, here is the reason: XP does not support GPT disks and I just got a new 3TB hard drive I want to use as a backup drive. I am not completely sure as to which forum to post this thread into so I apologize in advance if this is the wrong area.

What motherboard do you have? Did you download the Windows 7 drivers from that website and install them for all of your motherboard devices?

If you did, and that particular external RAID card doesn't work, you might have to find one that supports Windows 7.

Well, if that's the case, I think you have two options. One - buy a new motherboard. Two - Buy a different external eSATA/RAID card that has Windows 7 drivers. Personally, I'd update the motherboard first.