Problems connecting a camcorder via firewire.

[OM]

I'm having amazing trouble connecting a camcorder via firewire. :(

I have a PC... Windows XP installed, no service packs, software
firewall (Kerio), no antivirus.
I connected the camcorder 2 days ago... and it was working!
BUT... yesterday and today, I've been pulling my hair out... it JUST
WON'T see the damn thing.

I tried on another PC. This has all latest service packs, BIOS
uptodate, software firewall (Kerio), AVG Antivirus.
Same problem: it won't even see the damn thing.

I thought there might be a problem with the cable or the firewire card.
I tried an external DVD writer... connects fine, always recognised as
soon as it's connected.

I have tried the camcorder on 2 other PC's, with 3 different cables.
SAME problem. :(
(On one of the PC's, I tried turning the firewall and antivirus off, no
effect.)

OK... then I tried another camcorder.
Same problem: it won't even see the damn thing!! :(
(This camcorder also has USB connections. This work fine when the
right driver is installed.)

Then I tried ANOTHER camcorder (that connects fine on Macs via
firewire).
Same problem.

What am I doing wrong? :(

I really am going mad over this.

Any help would be appreciated.

Thanks.


Jam