Originally Posted by
snootyjim
We had that problem with a top-end Netgear N router and a top-end Netgear N wireless card with external antenna, so no it wouldn't necessarily help.
Try to check the channels nearby, see if there's any interference you can avoid by changing channel again. I know you've already tried, but it can't hurt.
Then try adjusting the antenna (if at all possible).
If you still don't have any luck, then maybe it's a dodgy wireless card in some way, as you suggested. I would be tempted to grab a cheap USB wireless adapter, and test with that. I've found these to be excellent in the past, and it's certainly a lot cheaper than a new router.