1.) Download the hldsupdatetool from [http://storefront.steampowered.com/download/hldsupdatetool.exe]this web site[/link] and save it to your desktop.
2.) Run hldsupdatetool.exe and when the installation wizard asks you for the destination folder click browse and enter:
c:\srcds
3.) Finish running through the installation wizard by clicking next a bunch of times.
4.) Go to Start > Run and enter cmd.
5.) Enter the following commands to update your server to the latest version by pressing enter after each:
cd c:\srcds
hldsupdatetool
6.) Once the command line blinks press CTRL-C to bring c:\srcds> back up again.
7.) Enter this final command to download all the files needed for a TF2 server:
hldsupdatetool -command update -game "tf" -dir C:\srcds
It will take a good hour or so to download everything so give it time. Once it is done a message will appear saying it has finished and you can exit the command prompt by entering exit.