Dec Updates cause device problems

I am running XP Pro with 512mb ram 120gb HD, DVD player, DVD burner, 3.5 disk
and of misc software. After the update, took place on Dec 15 for me, I would
come in and my PC had re-booted over night.. message the first time was a
device driver was bad.. took me to the MS site with a link to Nero for an up
date.. also my mouse was some what jumpy.. it would not move smooth across
the screen.. Oh I did the updates... I finally decided that it was MS that
had caused the problem so I removed the Dec patches and everything is almost
back to normal the mouse is a little jumpy but it does not re-boot all the
time... oh and no I did not put on any new software... so what do I do now..
I am behind a firewall and the update message is not clear as to what would
happen if I did NOT install it.. someone could?????