IT WORKS!!!
I had to disable the Windows System File Protector, setting it to ignore (only) rdpdr.sys, so that I could slip in the Win 2003 Server version of rdpdr.sys that pk supplied. Instructions on how to do this are here:
http://bitsum.com/aboutwfp.asp Skip right to:
Mod Method 5: Disable WFP permanently for specific files via patching the protected file list
More simple than patching executable code is simply patching the list of files contained in SFCFILES.DLL. First, copy
SFCFILES.DLL to a temporary file. Using a hex editor (i.e. UltraEdit), search for files to disable protection on inside
the temporary file. Once found, replacing the first character of the file name with 0 (that is: value 0 NOT ascii '0'
character). After completing the modifications, correct the checksum using our PEChkSum utility and set the temporary
file to replace the original at boot-time using our MoveLatr utility. Reboot the computer to finish the process.
I used HxD to edit C:\WINDOWS\system32\SFCFILES.DLL; there were ~5 instances of "r◊d◊p◊d◊r◊.◊s◊y◊s" ("◊" = null, hex 0x0). I changed them all to "◊◊d◊p◊d◊r◊.◊s◊y◊s"; fixed the checksum (Chksum.exe sfcfiles.bak); set up the file replacement (MoveLatr.exe sfcfiles.bak sfcfiles.dll); and rebooted. Worked fine (as evidenced by a quick peek at the new SFCFILES.DLL).
The needed utilities Jeremy Collake mentions are here:
http://bitsum.com/other/ WORKED LIKE A CHARM (Thanks Jeremy!)
THEN, I was able to copy the new rdpdr.sys (having saved a copy of the old one!) to C:\WINDOWS\system32\drivers & :\WINDOWS\system32\dllcache (for good measure), without the WinXP WFP "nanny" replacing the file!!
Tested RDP from Win7 client to the now-stably-modified WinXP sever: it worked fine; c
Reinstalled Avast! (ver. 8, free version). OK
And the
Acid Test: RDP from Win7 into WinXP --- with Avast! running --- IT WORKED! copy/paste, with drives mapped, worked in both directions.
Thanks so very much, pk!