Hi, Ive already tried installing topology discovery fixon my XP machine (having SP2) and it doesnt work (W7 and WXP still having problem with network). Can someone tell my other solution or what was wrong on this?, (W7isntconfigured with"Homegroup") Thanks,

Check to see if Windows 7 is in a HomeGroup. If it is, take it out of the HomeGroup. Windows 7 in a HomeGroup can only network with other systems using Windows 7 and Vista systems that are in the HomeGroup network environment.GA P35 DQ6 Mb, Intel Wolfdale 8600 3.33Ghz C2D CPU., 4x2Gb Mushkin DDR2 1066 PC2 8500 Ascents Memory Mods., PNY-nVidia GE Force 8800 GTS (640MB), 4-Western Digital Caviar SATA(2) HDD's (internal), 1 EIDE-USB External; Hauppauge PVR 1600 TV tuner, Dual Monitor: (1) Standard up top, (1) WideScreen below; Altec Lansign Speakers...

Check if he two systems are into the same workgroup: the default for 7 is WORKGROUP may be XP is MSHOME?Config: Acer: Aspire X3200, AMD Phenom 9550 ( 32-bit Quad core ), 4 Gb MB: Acer WMCP78M, Chipset: Nvidia; GeForce 8200 MCP78PV

You say Windows 7 isn't in homegroup, but is it in the same group as your Windows XP machine?