previous driver question... also cure for black screen

After Vista install and SP1, I put Nvidia 169.25 vid card driver on.
Recently, in the quest for scores, I put 174.74 (beta) on.
I run Aero.
All is well.

Whenever OnAir GT HDTV starts up Vista automatically changes from Aero to
basic. And back to Aero again when I stop the HDTV program. All is well.

Got a new monitor (Hannspree HF289H)
Installed the driver for it, and all was well.

Started the HDTV program and all was well.
Stopped the HDTV program and got a black screen.
Couldn't do anything with it so finally ctrl-alt-del got screen allowing me
to log off, and then log on. Vista is nice!
Fine, but the Hannspree driver was missing and the monitor was now non-pnp
at max of 1300xsomething or so (was 1900 x 1220). re-installed Hann
driver, but it didn't see it. I finally went to Programs and Features and
uninstalled Nvidia Drivers, expecting to remove 174.74 and wind up with
basic nothing.

What I wound up with was the previous one 169.25, and a working Hann driver
and all is well and I can run Aero start and stop the HDTV with no
blackness.

So all is fine...

But I wonder why/how I wound up with 169.25 ? Is this a result of the new
sxs thing? or what?

tia!

--
Kris
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DFI Infinity Blood-Iron P35-T2RL | E2200Alen 2.2@2.86 TtP0310
| 2x1gb Mushkin HP 800@1040 | MSI NX8600GTS-OC 256mb |
Raidmax RX530-SS psu | Vista Ult 32 SP1