Dunno if this will help improve anyone's in-game performance, but it
seems to work for me so here we go:

1. Download Process Explorer from SysInternals (great guys!)

http://www.sysinternals.com/ntw2k/freeware/procexp.shtml

This is a far-more featured Task Manager, but the only extra features
that concern us is how it displays the EXE for each task.

2. Boot up your PC, let it 'settle' and then firstly - close anything
that you can using its own UI - go through the taskbar tray especially
- these might be little icons but some of them leave quite a
footprint.

3. Now to get all the others... Run Process Explorer.

4. Notice two things: Firstly that it shows you the "Description",
from the EXE (if present), for each task. Secondly, notice how if you
hover your mouse over a process, it'll give you the full path to the
EXE that this task is running from.

5. Now this information should help you quickly identify all the tasks
that are superfluous to your HL2 session. Things running from Program
Files will often be of no use (widgets, toolbar extras, Acrobat,
Quicktime, handheld or mobile syncing widgets, SETI stuff, eBay or
Google toolbar, Messenger services etc..), whilst you're playing HL2
and just take up memory and resources.

6. Kill all the stuff that you know is crap (select the process and
press Del, or right click on the process and select Kill Process).
It'll be best not to kill anything that's running from your Windows
directory unless you are *sure* it's not part of Windows. You probably
want to avoid killing Steam since you're gonna be playing HL2..!

7. Notice how unlike Task Manager, Process Explorer uses a tree layout
- this shows you which process kicked off which - the parent process
being the parent in the tree. You should find that most of the
processes that you kill will have been started underneath the Explorer
process, and that you won't have killed much (if anything) underneath
the System process.

8. OK, so now you should have a PC running little more than the OS
itself and you should be ready to boot HL2 - hopefully to play a
little smoother than before.

9. When you exit HL2 and your PC has finished thrashing the HDD to get
rid of HL2 from its virtual memory (a process known as letting off
Steam...!), then you should simply reboot to restore your PC to its
normal state.

Hope that helps, obviously I'm not responsible if this screws
something up since I can't possibly know what processes you all have
running on your PCs.. But you should be fine with this. Perhaps err on
the side of caution first time around. I tend to find that I can kill
about half of the processes running.. perhaps I've installed a lot of
crap on my PC!

andyt