Help Miserable wifi - how to tell if this is broken?

[tentacle]

Android Version: 2.2
Network: wifi
Are You rooted & which Rom: yes, um i dont know, perhaps stock HTC 2.2 since there is HTC Sense installed?

I just bought a second hand HTC Desire that came to me rooted and with 2.2 installed. It also has s-off installed. I did a factory reset just to be clean.
Everything's fine except wifi performance is utterly miserable. I have to literally be within a few meters of my AP for it to work at all. Wifi Analyzer shows signal strength to be in the red or even below at all times.

I have two APs (different model and manufacturer entirely) and both are as miserable.

Is there any chance this "2.2" might be some semi-broken rom as opposed to the official HTC update? Might switching to something like cyanogenmod make any difference?
Any way I can be sure it's a hardware issue before I send it off to HTC for 4+ weeks? Does anyone have any idea what this kind of HTC repair trip might cost?

Any help much appreciated.

 

[SUroot]

Well

1)It could be the rom its using (what is it?) having a dodgy wifi set up on it

2)I have heard of wifi problems on ex-orange handsets. Was the phone branded originally do you know?

 

[tentacle]

1)It could be the rom its using (what is it?) having a dodgy wifi set up on it

Im installing cyanogenmod 6.1.1. now, we'll see if that makes a difference. I'm a little unclear on what this flashing radio bit in the instructions is all about or how to even check what radio version i have.

2)I have heard of wifi problems on ex-orange handsets. Was the phone branded originally do you know?

No idea really. No traces of anything orange in the software, but I guess it couldve been debranded.