Huge Wireless connectivity drop d-link DI-754 802.11a

My Di-754 D-link router has been acting up lately.

The wireless connectivity has dropped significantly. Where I used to have very good connection, I now have bad to very bad. And we're talking about 3 feet here. I've two laptops, one in the room with the router, 4 feet away, and the other in another room, 7 feet away including wall.

I can set up an ad-hoc network from one laptop to the other, which has 'good' connection.

I can connect to the internet without a problem, I can plug in the utp-cable from router to laptop, and everything is nice and dandy. My VOIP is working fine too.

It is just really only the wireless part of the router.

Now, I have to be honest, at one point I mistakenly put my dc-power supply from my VOIP (at 5V) into my D-link DI-754 router and vice versa. This had the result that the voip box was not working, while the router had loss of connectivity (but was essentially still working) I found out about my error and plugged it in the right way. The VOIP box is working fine now, but the wireless router still has bad coverage.

I have installed a new firmware on the router, with no effect. I have tried a crash reboot, but I am unable to upload the file, there is no data transfer still after 30 minutes.

So, now come the questions.
1. Could I have crashed the wireless router by plugging the wrong adapter (same voltage though) in?
2. Do these symptoms suggest this?
3. Can a crash recovery firmware flash help?
4. What can I do to fix it.
5. Or should I toss it..... and get a new one?

Thanks for your help

I agree with hubbardt try the factory reset and if that doesnt work most D-Link products have lifetime warrenty just avoid mentioning the wrong power supply thing.

The one month is just from the seller. d-Link should honor the warranty.

Most have a special sequence to clear the flashram, then reload the firmware. I've done it with SMC products once. That may be the only way to reload corrupted firmware, may have to be connected to Lan port1. May have to contact D-linke to get theis procedure. They generally don't publish it.