Intel 5100 wireless card problems

Hi all, first post after reading the forum for a few months

I have an Acer Aspire 1810tz that came fitted with an Intel Wifi Link 1000 BGN card, recently i had to replace my router and i decided to go with a dual frequency (2.4 and 5ghz) Linksys/Cisco jobbie.
I can connect fine but im finding i get low signal strength on the 2.4ghz network.
To cure this (or so i thought) i decided to upgrade the internal wireless card with an Intel 5100 dual frequency card brought "new" from ebay, problem is i cannot get it to work.
I tried the Intel drivers but it would blue screen on boot up so i un-installed everything and re-installed the Acer drivers for this card direct from Acer support, all went well, it booted, recognised the card and installed the correct drivers, problem is, every time i enable the wireless card via the front switch i get a BSOD!!!
This is bloody infuriating and i cannot figure out if A: the ebay bought card is faulty, B: the card is unsupported in this model or C: i need a bios update (cant see it my self) from the stock on it came with 6 months ago.

Any help greatly appreciated

Sharpcroft