How do you do a keyword search the Services.msc (mmc) window in Windows 7?

sc.exe at the command prompt OR the *-service set of PowerShell tools.

At the command line, sc can do a bit of service frobbing and you can combine that with outputting to a text file or messing about with find. But really, you should be using PowerShell these days so Get-Service (as well as Start-Service, Restart Service, Set-Service, etc.) combined with the myriad of PowerShell supplied formatting and parsing tools is your best bet.

Here's an example in PowerShell:

$t = '*mana*';Get-Service | Where {($_.Name -like "$t" -or $_.DisplayName -like "$t") -and $_.StartType -ne "Disabled"}

it filters in both name and display name and ignores disabled services.

You could put this into a script Find-Service.ps1 with a single parameter.

 param(
 [string]$term
 )

 $term = "*" + $term + "*"
 Get-Service | Where-Object {($_.Name -like "$term" -or $_.DisplayName -like "$term") -and $_.StartType -ne "Disabled"}

xnet.exe available from a few locations (e.g. http://www.netware.se/en/downloads/) can list all the services running - you can then use something else to search the output. Handlily xnet also reports the short name of a service, which can be used to manage it.

HKLM\System\CurrentControlSet\Services can give you a lot of info that you might want. Tread with caution.