Thanks for all your replies!
It's a Dell Inspiron 660. It came with W7 and I reformatted the harddrive and installed Windows Vista 64Bit Ultimate.
I think the router is in mixed mode (b/g/n), but I'm not sure. I can't find anything about it in the router settings. The router is a Netgear N300 Wireless Gigabit Router, model WNR3500Lv2. It says "IEEE 802.11 b/g/n 2.4 GHz" on the outside of the box it came in.
I also could not find anything about MAC authentication in the settings.
The security options available are:
1) WPA2-PSK [AES] (currently set to this)
2) WPA-PSK [TKIP] + WPA2-PSK [AES]
I'm very thankful for further assistance in solving this problem.
PS: I forgot to mention, I also have a Windows XP computer that I am trying to connect to this router, but it's having the exact same problem as the Vista computer. I am not 100% sure what the wireless card in it is called (but it does detect my wireless network, just isn't able to connect), however I just thought I'd mention the Vista computer is not the only computer having problems connecting.
On the other hand, I did have a laptop brought over (with Windows 7) and that connected like a charm, which proves the router is not malfunctioned (it does state on the box that it's compatible with W7, Vista and XP).
This was what lead me to believe that it's a driver issue and not a router setting (I've been thru alot of tweakings of the router settings together with Netgear support, to no avail).