I had a very similar problem with my new ACER Travelmate 4070 runnning
MS XP Pro.

I started Task Manager and with a lot (like A LOT) of persistence and
patience, eventually identified that my machine was running a process
named QtZgAcer.exe

When I searched on the web, I found a number of forum/discussion board
entries that stated that this file appeared to be causing Acer
machines of all vintages to "hang". This file relates to the Acer
Launch Manager which I think allows configuration of the soft function
keys (also known as programmable function keys).

The workaround on a couple of these forums was to uninstall Acer
Launch Manager.

Since I did that last week, I have not had any problems. I will wait a
few more days/weeks before I can be absolutely sure that the "hanging"
problem has gone away.

BTW - I wrote to Acer tech support at the Acer site and have had
absolutely no response. Not even so much as a "thank you for
contacting Acer support"!!!! Someone at work did recommend that I did
not buy an Acer..... maybe I will live to regret the decision.

You could try uninstalling Acer Launch Manager if you do not use the
soft function keys. At worst, you could re-install the software later
if you want to.