New Bell 1000 wifi modem replacement, causes atapi 11 errors??

BACKGROUND

Had line issue and the tech came to visit, "you've got a really old modem", and a little voice goes off 'yeah, but works fine and if it's not broken...'.

Anyway, it got replaced with this Bell 1000 wifi modem. Looked fine, but after a while noticed odd hickups when opening multi browsing sessions. Then when gaming, omg long loads.

Did pull full powerdown of the PC, PC couldn't get past the Windows (Win7 32 bit) screen to the password. Forever loading.
I go, 'Oh I know this one', pull the power off the modem, PC boots fine. Games run fine.
Look at event manager, when the modem is running, tons and tons of ATAPI 11 errors. None of those without the modem.

PROBLEM (tl;dr)

Modem switched from old basic model to wifi version (ISP supplied).
With it working, lots and lots of ATAPI 11 errors. PC won't even boot. Pull the power on the modem, everything fine. Once up and running, plug it back in to get net access.
Can use the net, so long as not too many sessions opening it's mostly ok. Do to many, get 20 second system locks.
Don't know what's up (hate these kinda generic errors), thought ATAPI was more HD stuff. No 11 errors with it powered off.

Ideas?
Many thanks.

You were almost right about ATAPI. Anyway, I can hardly imagine how the modem could even be indirectly responsible for those errors. Copying one of those events and posting it would be a good place to start, but I have a feeling this will be one of those issues that doesn't get solved to any degree of intellectual satisfaction. I found another thread in which one user apparently solved a similar issue by re-connecting a USB device that was disconnected following a power loss. WTF?

Had some free time to do some digging around. More info.
DCP Latency... if anyone's gone down this path.....

** Definitely W7 issue, not hardware.
- I have 2 HDs in this system, each with it's own OS. Old XP version, and the current system which is W7. I always backup the system partition of one onto the other (while I move over OSs, I sometimes boot from either, works well).
- So fired up the old XP system, and installed the new network and it works fine under XP.

Potential DPC (deferred procedure call) issue in my W7.

Used a DPC latency tool and get many hits (long waits) in my W7 install.
Tried it in my XP OS, nothing, all in the green.

I STILL have DPC latency in W7 with the modem disconnect, which makes sense as it doesn't cause DPC issues when I plug it in while running under XP.

So that DPC is the only thing I see common in all cases, but not sure why it's an issue or why it has no effect without the modem (or at least noticible ones). BTW, Windows troubleshooting and checking all devices, W7 says everything OK.

** Tried the clean boot.
Even with only the W7 services running, same DPC issues, same lockups.

?? So, any easy way (considing W7 things everything is fine) to find out what device/driver is causing these DCP issues which seems to be the only thing in common?