I have a similar problem ever since I upgraded PC-Suite to ver. 7.1.40.1 - prior to upgrade PC-Suite functioned normally (in it's partial manner).

I'm using Windows 7 PRO x64 with Data Cable CA-101.

I can no longer connect my phone to the PC in PC-Suite-MODE (it still connects in Mass-Storage-MODE).
When plugging the cable I get the following message (by the OS):
"Device driver software was not successfully installed".

Clicking the error baloon brings up a list of 5 drivers:
- Nokia N900 USB Phone Parent (Ready to use)
- Generic Phone (No Driver Found)
- PC Suite Services (No Driver Found)
- SYNCML-SYNC (No Driver Found)
- Nokia N900 USB Modem (Ready to use)

In Device Manager (Windows) the three "No Driver Found" devices are shown with an exclamation mark.

Attempt to locate and install driver software manually (pointing to PC-Suite's location on hard-drive) gives the following message:
"Windows found driver software for your device but encountered an error while attempting to install it."
(Nokia N900 USB OBEX/Nokia N900 USB Generic)


I've attempted to uninstall all NOKIA software and ran the PC Suite CLEANER. However, sub-sequent re-install (including older versions) didn't help.
All installations were also attempted in XP-SP2 compatibility mode and Run as Administrator was checked.

Interesting to note that the phone still connects to my Laptop after a similar upgrade. The Laptop is running XP-SP2!
So it certainly looks possible that this is a Windows7 drivers issue but in my case only with the new PC-Suite.

I see that you've stumbled upon this problem quite some time ago, Have anyone found a solution to this issue?