FIXED!
Just install the Tiberian Sun LAN patch* ...it works on Windows 7.
( You don't have to use the third party service XWIS !!!)
*Full name of this patch: Tiberian Sun / Red Alert 2 LAN Patch v1.00 by Scorpio9a
ts_ra2_lanpatch_1_00.zip ...includes file wsock32.dll
