My router hates Mac?

Here is what's been going on for a very long time- almost a year now. As my computer is nearly useless without internet (for work and school) I REALLY need to figure out how to fix this problem, or get rid of the computer.

I have a Linksys W10 router that has worked fine in the past. After an update almost a year ago, my MacBook (v. 10.5.8 update) won't connect to the router. Keep in mind that I work only about 5 ft away from it.

But it gets more interesting...

SOMETIMES, I can connect if there are no other computers using it (even though the connection is very slow). As soon as my boyfriend powers up his computer, internet is no more. The wireless signal is there, the connection is not. Even connecting the ethernet cord does not help matters!

Also, I have a netbook that has become my main computer because of this problem and it connects perfectly.

MOST interestingly, if I take the MacBook to school and use the WiFi there IT WORKS FINE. So I have installed updates, etc, but still no fix.

So the router works, but not for the Mac. And the Mac works, but not for the router.

A friend thought it was a conflict of IP addresses, so he tried putting a static IP on. Still no fix.

Has anyone heard of this problem before? I don't want to buy a new router only to have the same problem again.

Thanks to anyone who has read this and please let me know if you have anymore clues or insights to this problem,

A very vexed Samantha.

You could probably improve your wireless by doing 2 things adding Locations for most frequently used sites, like Home and Uni and setting each of those Locations up with the DNS numbers of the ISP at that Location if they do no show up automatically. Look here and here to do settings in Sys Prefs/Network/Advanced/Airport. Leave automatic for casual roaming.

UPDATE:

For anyone who has had a similar problem, mine has been fixed. It turns out that when the network mode on the router was set to 'mixed' it automatically set to 'wireless-n' which is the newest and which is no good for "old" macs (mine is 4yrs old). This makes sense because the other computers that use the router are very new.

We changed the network mode to 'use wireless-b only' and it works fine now since it is an older type of signal that works with my wireless.

You should get a simultaneous band router that way you can enjoy both n and b wireless

Hope it's ok if I ask another question - along the lines of not being able to connect my new MacBook Pro wirelessly to a new Netgear router...

I've tried all 5 different ways to set up the security but I can't get my Mac to connect unless I'm plugged in (Ethernet). But my Vaio PC connects fine. I will go back to the Netgear site to see if I can find out anymore about set up, but I'm hoping someone here could tell me what I can try to solve this without completely opening up the security.
And, BTW, am I supposed to name the 5GHz and 2.4GHz gateways with different SSIDs or use the same one for both?
Thanks so much!

It would be more beneficial to name them differently, that way you can distinguish what band your on