The error I get is Windows can't enable Firewall and that I should try to enable it myself via the control panel. But if I open the firewall-control panel i get an error saying "Because of an unknown problem the configuration can't be displayed" (attn: I have a dutch version of winXP, so it's translated).
But the biggest problem now is that my PC crashes every session. I get a critical stop 0x0000008E (0xc0000005, 0xf4bd39fe, 0xf2a00a28, 0x00000000).
I know this is a memory-problem, but in safe mode I don't encounter this problem.