So... you have used some sort of script or a variation of a script as shown below via your active directory GPO and have no problems before.
Bam... you adopt Windows 7 and it now will not map. You searched various forums and found just as many people asking the same questions.
Set objNetwork = wscript.CreateObject("WScript.Network")
strDriveLetter = "I:"
strFileServer = "\\sharedrive.yourexample.com\"
strUserName = objNetwork.UserName
objNetwork.MapNetworkDrive strDriveLetter, strFileServer & strUserName
Before you pull your hair out, try this fix. Run regedit on your Windows 7 box.
Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System
Create New DWORD Value with this name EnableLinkedConnections
Right click and select Modify... on the DWORD created above
Value data: 1
Base: Hexadecimal
Exit and restart computer
Good luck.