PnkBstrA.exe is normally a legit file. However, it can also cause problems.
Do the following and see if it helps.
Download the following program:
http://www.evenbalance.com/downloads/pbsvc/pbsvc.exe
Open the program above and click the "Uninstall" button. This will remove the PnkBstrA.exe and PnkBstrB.exe service.
Some may need to rmove the registry entries.
Go to START --> RUN .. type regedit
search in these parts
HKEY_LOCAL_MACHINE\SYSTEM\Controlset001\Sevices look for PnkBstrA PnkBstrB and PnkBstrK .. just right click on the folder listed on the left and delete.
HKEY_LOCAL_MACHINE\SYSTEM\Controlset003\Services look for PnkBstrA PnkBstrB and PnkBstrK .. just right click on the folder listed on the left and delete.
Also in C:\windows\system32\drivers is PnkBstrK.sys .. safe to delete.
Evo,to ti radi probleme.... :)