You did right and it's good that you took the initiative. You're already halfway to managing your system correctly by doing so.
Yes, there are forums dedicated to this sort of thing and you have found them. Any questions, just fire away!
Where security is concerned, have a look at [highlight]
this post[/highlight].
Where optimal running is concerned, remove anything you don't use via the Add/Remove Programs applet and don't forget the Windows section.
Have a close look at any large program installations such as Office and uninstall any unused features.
Keep temp folders and temp internet folders as clean as possible.
Make regular backups of your personal data.
As for all that saved cash, donations can be made to.........