DPC and Interrupts Spikes CPU w/ Wireless Card Inserted - Task Manager Incorrect

I've been trying to save a friend's emachine m2105 notebook.  They were complaining about it being slow. 

 

Using task manager I saw that the idle thread did not match the CPU usage summary (say idle was showing at 90% and CPU use was showing at 60%).  This set off some red flags.  Computer had up to date spybot, ad-aware, symantec corporate 9 av, and windows defender.  All scans were negative.  I have made no attempt thus far at scanning for rootkits.

 

Using Procexp I saw that CPU was being eaten by DPCs and interrupts.  Windows defender was using a fair amount as well but uninstalling it did not solve the main problem.

 

Through trial and error I determined that the high DPC and int was only present when the wireless pc-card was inserted (a zyxel card in this case).  Spike occurs the moment the card is inserted and ends when it is removed.  I tried another wireless pc-card (realtek) and the spike occured as well, even before I installed drivers for this card.  I do not presently have non-wireless pc-cards to test with.

 

The machine has had several different wireless cards in the past though the software for those cards was removed via add/remove in control panel.  An old prism based card left an icon (snap in?) in the control panel called 'prism' that I do not know how to remove.  I am unsure if any of this is related to the problem.

 

I have tried a variety of chipset drivers (the stock from emachines from several years ago and the newest from intel from feb).   I have uninstalled the cardbus control from device manager (TI based though I do not have the exact chipset on hand).  I have reinstalled the wireless card and drivers.

 

I would very much like to avoid a clean install.  If anyone has experianced a problem like this or has any ideas, please let me know.

 

Thanks