I installed the modem driver even though I doubt I'd use it. Thanks.
I'm starting to wonder if the 'unknown device' is one of:
*Battery - is there a driver for this? edit: I have solved this? *see below
*Intel chipset - how do I know if this driver is installed
*keyboard - Thinkpad keyboards have a lot of functions and I don't see 'IBM' under keyboard in Device Manager
If any of these need to be installed, I would have a problem or more confusion.

I only have the one question mark left! ????
EDIT: How about I try to make it simpler?: This is what is currently in my Drivers directory which is: C:\Drivers\Win:
Audio, DISPLAY, ETHERNET, IBMPM, INTELINF, SWMDMLUC, WLANINT and *now* BMMPM...
Is there any that shouldn't be there or any missing?
Re how difficult Thinkpads are to strip etc, if you think they're bad you should see what most other manufactures are like - TP's are actually amongst the easiest to pull apart and rebuild and have probably the best documentation too
Yes, I am sure you are right. I've seen techs or laptop techs in stores fix them fairly fast. I think it's my inexperience with them as all my hardware experience has been desktops (not barebones machines but ones with individual components to be put together). Also, I was initially frustrated with my incompetence. Once I found the 'unlocking' switch and figured out which way the drive went, it wasn't so bad.
So, mostly my mistake. Sorry for expressing my frustration!