You mention "since a few weeks"...did this computer work fine on the router previous to a few weeks ago? If so, can you think of anything that may have happened to the machine around that time, or possibly did you install any network-related software, a VPN, etc.? You could always wipe the system and reload the OS in order to rule out software as being the issue. A friend had a similar problem, and it went away when he wiped the system and went to Snow Leopard. Obviously Snow Leopard will not work on this system, but my point is that a fresh install may help. And of course make sure it is fully patched, because very early revisions of any Mac OS tend to have networking and especially wireless glitches.
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You mention "since a few weeks"...did this computer work fine on the router previous to a few weeks ago? If so, can you think of anything that may have happened to the machine around that time, or possibly did you install any network-related software, a VPN, etc.? You could always wipe the system and reload the OS in order to rule out software as being the issue. A friend had a similar problem, and it went away when he wiped the system and went to Snow Leopard. Obviously Snow Leopard will not work on this laptop, but my point is that a fresh install may help. And of course make sure it is fully patched, because very early revisions of any Mac OS tend to have networking and especially wireless glitches.
You mention "since a few weeks"...did this computer work fine on the router previous to a few weeks ago? If so, can you think of anything that may have happened to the machine around that time, or possibly did you install any network-related software, a VPN, etc.? You could always wipe the system and reload the OS in order to rule out software as being the issue. A friend had a similar problem, and it went away when he wiped the system and went to Snow Leopard. Obviously Snow Leopard will not work on this system, but my point is that a fresh install may help. And of course make sure it is fully patched, because very early revisions of any Mac OS tend to have networking and especially wireless glitches.