BenQ CD-RW 5224P firware problem

I installed new firmware K.UC for my BenQ CD-RW 5224P (old v. FW K.JC), I checked FW version with BenQ tool. After installation my BenQ didn’t respond on eject button, I restarted comp. and in tray icon message appeared saying “Found new hardware” “CD-ROM”. After that windows was completely slow, more like frozen. I can’t do anything, only I can do is to disconnect drive and than everything works OK. In BIOS is everything work fine and in Command Prompt.
config: Acer PowerSD, P IV 2,4 GHz, 512MB RAM, Win XP sp 2, (PM) HDD, (PS) none, (SM) DVD-ROM, (SS) BenQ CD-RW 5224P 52x24x52.
Please help!