Vista - wireless network card(s) - epic fail

since building a new rig last christmas ive had endless problems with wireless networking.

specs:

asus p5q-se
intel e8400
4gb corsair dominator ram
palit hd4870 1gb
seagate sata II 500gb
corsair tx series 650w
vista ultimate 64 bit

wireless cards: d-link g510 rev C and Asus wl-138g v2

With the g510 i can get a connection to the internet but im getting only 1mbps despite 22mb internet, browsing and downloads are painfully slow.

With the wl-138g i can only get a local connection or connection with limited access.

Ive tried everything i can think of:

Wipe, reinstall and try new drivers,
tried all pc slots
removed second stick of ram
updated bios, cleared cmos
reinstalled vista

I've even installed xp on a spare hard drive and i get the exact same problems.

After all this, i thought i must have a faulty mobo so i returned it to the reseller, they told me they have "confirmed the fault" and sent me a new one.

Yesterday i put my pc back together without any cards, installed the asus drivers and put the card in, connected fine and got good speeds on the internet. I rejoiced and celebrated, thinking it was all over.

Then, this morning i booted up and i got no connection at all, after loads of tinkering im back to square one and both cards are operating like they did before the motherboard replacement.

Now, i have no idea what to try next and how to get this fixed.

Please, help me out!

Wireless A is what I use (I have a A/B/G card), while my wife and desktop computer use Wireless G
I have 19MB (19587kbps) down, 3MB (3743kbps) up. it also depends are your High speed Internet access, are you using DSL, Dial up or High Speed cable?

perhaps you should look at "available" networks , I suspect many are on the same G network which will make it sluggish. Try going into the router and change the channel. Try 11, and others untill you find one that is faster.

Dumb question but... why can't you run that rig "Wired" instead?

Have you tried Disabling IPV6?

Have you updated the wireless adapters to their latest firmaware/drivers?

Have you disable the onboard adapters... if any?

What kind of router are you using? Latest firmware?

Have you tried using "OpenDNS" as your DNS carrier? if not, goggle it and try it.

Internet is DSL, ive played around with channels a bit, but i dont think that it would affect my speed to the extent that it has. I think its more of a hardware problem...maybe.

and believe me i would love to just use wired. but 30m of cable from one end of the house to another is not going to happen.

Have you tried Disabling IPV6? yes

Have you updated the wireless adapters to their latest firmaware/drivers? yes

Have you disable the onboard adapters... if any? yupp

What kind of router are you using? Latest firmware? O2 wireless box III and yep

Have you tried using "OpenDNS" as your DNS carrier? if not, goggle it and try it. Tried it, no change

Try unplugging the dsl modem (kill power), then unplug Router (kill Power), then turn off PC
wait 10 minutes power on dsl modem, few minutes later power on router, then turn on pc.

ive tried that a numerous times and i either still get the slow connection with the one card, or no connection with the second card.

try a new router/card then-first connect directly to modem make sure its not that.

ive tried connecting to the router directly with ethernet by taking my pc downstairs and it was working great.

I normally connect my pc to my laptop and use my laptop as a network bridge, that gets me a decent connection.

Im thinking of getting another card but wouldnt be suprised if it had the same issues.

Well if it works under ethernet, then its one of two things; either the cards are bad (doubtful), or its User error, and you have messed up the Windows settings somehow. I suggest you restore to a point before the issues occured.

Another thing is to delete all wireless connections, then recreate them.