Atheros wi-fi on Aspire 4520 not working

hi all, a-slaam!
i got this laptop from a friend and foolishly decided to format it and start clean over again. i slipstreamed xP Pro x86 with SP3 and all latest drivers using nlite and got a clean, fast, wonderful load.
but wi-fi began giving problems.
on occasion it turns on. then works almost each time i reboot.i once left the laptop to go into suspend and the wi-fi stopped working. pressing the wireless button showed "no device"! various re-booots later, it continued to fail to detect the wireless card.
then i did another install using slightly different config and set "wireless zero config" to be started manually (thinking it might be the culprit).
it kind of worked as on next boot as it recognized the card. i started the WZC service to search and connect to my home wireless gateway. slipstreaming helped in not loading windows generic wi-fi drivers and only Atheros was loaded.
but sadly, it stopped working again.

however, when wi-fi does work, it works wonderfully! no problem with range or speed! terminal services and UDP and TCP work beautifully. all else like flashing orange light etc works absolutely fine each time the wireless card is discovered.
but when it fails, it is very disappointing!
thinking that the card maybe damaged, i tried the AR5BXB63 card on another machine and works fine! some one told me that the PC bus may be the culprit. and as i said, before the i took the decision to format it, it worked flawlessly.
i have the ACER-OEM original XP2OEM_EN CD which i used to slipstream. thinking slipstreaming was the issue, i tried another clean install (with all windows drivers and SP2), then upgraded to SP3 and the latest drivers, but the problem persists.
pl advice! i'm so frustrated with the machine that i now plan to use it as a desktop only! this is my first and only laptop! pl help me regain its mobility!
thank you again.
regards, govindra.