Press "Windows Logo + Pause" and then goto "Advanced System Settings" to change performance settings

Get System Info:

Type in Start Menu Search box
msconfig.exe - selective startup
msinfo32 - System Info
reliability monitor - List problems
performance - Detailed info. Memory, CPU, Network - 
  Specify sampling, data collected and reports
 or start > Control Panel > System and security > admin tools

resmon - CPU, Memory, Disk, Network utilizaation

performance information - Computes Windows Experience Index
  score from 1 - 5 for Processor, Memory, Graphics, Gaming Graphics, Disk
  or start > Control Panel > System and Maintenance start > Control Panel
     > performance info. & tools
     
task manager - list running applications and processes

Disable Services:
The standard way of disabling services was with the System Configuration Utility msconfig.
Black Viper recommends the management console (services.msc) (Type "services.msc" in the run box.)
With msconfig and Hardware Profiles, you can disable services that may be vital to boot your system. With the management console (services.msc) you cannot.
Black Viper lists several configurations each disabling more services at Black Viper's Windows 7 Service Pack 1 Service Configurations | www.blackviper.com

Other ways to list background processes:
Task Manager "Start Task Manager" (in Windows 7)
or right-click an empty area in the taskbar, and then clicking Start Task Manager.

Or download AutoRuns from technet.microsoft.com. See article windowsITpro.com
Start-up Applications - Do you need all of them? at pacs-portal.co.uk

Optimize Your Windows 7 PC | PCWorld
If you don't mind transforming your OS into a clone of Windows 2000, click the button that tells Windows to adjust its visual settings for best performance. It's a harsh step to take, though--if you'd prefer a piecemeal approach, uncheck only the boxes that relate to Windows Aero (such as Aero peek and transparent glass). You'll retain a semblance of a pretty desktop while still improving performance a teeny bit.

Turn off Aero Glass transparency:
How To Disable Windows Aero Transparency In Windows 7
Control Panel > All Control Panel Items > Personalization turn off transparency.
Then at the bottom click on Advanced Windows Color and Appearance make your choices the old fashioned way.

How To Disable Search In Windows 7 - How-To Geek
Disable Search Indexer and Indexing Service - KezNews.com

Multiple Ways to Speed up Windows 7

1. Reduce boot time by using two cores
2. Turning off the Minimize-Maximize animation
3. Trim your fonts down to just those that you need to use on a daily basis.
4. Improve shutdown by reducing the time Windows waits to kill processes:
5. Disable Search Indexing

Windows media - deactivate everything but default player :
Schedule Windows 7 Media Center Optimization for Better Performance - How-To Geek

Most techies use alternatives to Microsoft Apps for better security and/or performance.

Microsoft App	Alternative
Internet Explorer	Chrome, Firefox
Mail1	Thunderbird, Eudora,
Windows Media Player	VLC Media Player

1. Thunderbird was recommended over the old Microsoft Outlook.
Windows Live Mail has replaced Outlook in Windows 7 and is better. You may have to install it. See download and install Windows Live Essentials.
See:
Windows Live Mail Vs Thunderbird 3 - Clash of the Titans
Thunderbird vs. Windows Live Mail - Which is the Best E-Mail Client?

Disable Autoplay of Audio CDs and USB Drives at How-To Geek

Windows 7 How-To Articles, Tips, and Guides :: How-To Geek
  Use Advanced Tools to Troubleshoot Performance Problems in Windows 7 - How-To Geek

Books:
Mastering Microsoft Windows 7 Administration

Other Links:
Black Viper's Windows 7 Service Pack 1 Service Configurations | www.blackviper.com
TweakHound - Tweaking Windows 7 - Recommended services to disable
SourceDaddy - Windows 7 Tutorial | Disabling Unneeded Services - Lists function of servies.
  Windows 7 Tutorial - Removing Extra Fonts for Speed
Windows 7 Default Services Configuration Startup Type and Log On Account - The Winhelponline Blog
Optimize Windows 7 for better performance at Microsoft
  AutoRuns will allow you to remove items from the list of programs that automatically get started at boot time.

Multiple Ways to Speed up Windows 7
Windows 7 Home Premium Setup at dmcritchie.mvps.org