Well it's definitely not a driver issue, because those are the genuine drivers for that card/chipset. Plus, it works when you install it on the Win2K machine. So it's probably an IRQ conflict like you said or, more likely IMO, some kind of Windows Registry/INF glitch.
<< Weve found out that the modem is on IRQ3 and assigning itself to COM3 >>
Well, PCI modems don't really use COM ports. They install a little redirector driver in case old school programs are accessing them using DOS-style COM ports. But most software now access modems directly through the Windows TAPI interface. Your PCI modem is almost certainly using another IRQ besides 3: usually 7, 9, 10, or 11. Use Programs > Accessories > System Tools > System Information to check for conflicts.
But I don't really think that's the problem. Like I said, the modem's presence in Device Manager but not the Modem control panel seems to indicate a Windows registry/INF glitch.
Are you due for a format/reinstall of Windows on the HP machine? That would be the best way to completely eliminate software as a variable. If you're not willing to do that, then do your best to clear out all driver references from Windows. To do that, first use Add/Remove Programs to remove anything related to modem drivers (yes they often put themselves there) then follow these instructions from my FAQ article:
*** FIRST make sure you have copies of drivers for all your hardware ***
In Windows 95/98/ME:
The procedure is similar, but the registry keys are found in different places, and may be consolidated together. Delete all keys and values UNDERNEATH these keys:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\VxD
HKEY_LOCAL_MACHINE\Enum
Even after removing devices from Device Manager and a thorough hatchet job on the Registry, driver files will remain. Don't worry too much about this as these files are largely disassociated from the operating system now, and they amount to little in terms of storage. There are some, however, that can still haunt you from beyond the grave. These are the files found in the INF folder under your Windows folder.
INF files are like the table of contents for a driver package. They tell Windows what files will be installed, where to reference them in the registry, and what the default device settings should be. They also contain specific PnP vendor ID's that identify exactly which hardware they're intended for. When Windows is "building a driver information database", all it's doing is reading through every INF file in the INF folder. Then, if it detects a PnP device that matches with a known vendor ID in one of the INF's, it installs whatever driver files the INF tells it to.
When you install a new device, its driver's INF file is copied to the INF folder. You want to purge these. Some of the INF's, however, are part of Windows' default device support, and shouldn't be removed.
In Windows 95/98/ME, it's easy: kill everything in WINDOWS\INF\OTHER. That's where new INF's get dumped.
Modus