Disappearing wireless drivers!

Hi there, I recently installed a wireless router and wireless laptop card.(Lappy runs XP) All was working well until I found I couldn't access newsgroups - updated my firmware and all was solved. However since then (could be coincidence), I have been unable to maintain any sort of signal between router and laptop for any more than about 2 minutes, even when sat next to the router aerial!

It occurred to me that the firmware update may have caused some issue in signal so I had a look at the card and router settings and nothing seemed amiss. I then noticed that in Device Manager the wireless card had a yellow exclamation mark on it - dug a bit further and says that the drivers may be missing or corrupted - Code 39. I haven't touched them!

Anyway, I ran through the troubleshooting guide and ended up uninstalling the driver, restarting and reinstalling again - no change, it won't recognise the card when I plug it in (says that I mustn't plug in before installation) and still shows the excalamation mark and error message.

Can anyone understand what might have happened - as it's a new laptop I haven't been using it much and nothing untoward installed, nothing in fact apart from what came with it. I've e-mailed the card manufacturer but may be waiting a while if their website is anything to go by - how can the drivers suddenly become corrupted when they were working fine before, and if they are, why don't they repair when reinstalled? Could this be a problem with my laptop instead?

Thanks for any assistance.