Generally, just use the free CCcleaner if you're so inclined.
If you have codec problems, you could also use the free K-Lite tweak tool to fix codec difficulties in the registry, but that's something you do only if you're really having trouble. But don't bother buying something. I wouldn't."
http://www.sunbeltsecuritynews.com/090519-CCleaner
http://www.sunbeltsecuritynews.com/090519-K-lite

I'll let others who like to comment on installation issues do so, but I find much of the nonsense tiresome. You can't give accurate counts of registry changes, as much of that is related to normal Windows housekeeping and unrelated activity. Counts are also meaningless. There's no such thing as "garbage" registry entries, that's a serious lack of understanding of how Windows works. Adding entries to the registry isn't a bad thing, the information needs to be kept somewhere. Whether it's in individual files or a common database is largely irrelevant. The database nature of the registry provides for fast access speeds largely independent of size, which isn't the case for individual files. Everything in the registry is there for a reason. Shell entries and associated most-recently used (MRU) lists are for providing the features of Windows Explorer. UserAssist entries are for providing the features of the Start menu. MuiCache entries are for providing fast access to the UI of programs which are multilingual. Anytime you see the word "cache" associated with computers, it's nearly always for providing speed. File open/save MRU lists are for providing drop-down options in file open/save dialog boxes. Statistics are used to monitor the performance of Windows for detecting problems. Tracking information is used for prefetch, Superfetch, and disk defragmentation. Cleaners are written and used by people who don't know anything about Windows. No one who knows what they're doing writes or uses "cleaners", they destroy the features and performance of Windows. Stick with Microsoft tools, like Disk Cleanup (and even then I deselect most things).
Comment by Fubar — June 6th, 2011 at 4:08 am

   

.fseventsd
.Spotlight-V100
.Trashes

._.Trashes

Click Start, click All Programs, and then click Accessories.
Right-click Command Prompt, and then click Run as Administrator.
If you are prompted for an administrator password or for confirmation, type the password, or click Continue.
At the command prompt, type the following command, and then press ENTER:
netsh interface tcp set global autotuninglevel=disabled
This command disables the Receive Window Auto-Tuning feature.
Close the Command Prompt window. Restart the computer.

Open Notepad. [Start -> All programs -> Notepad]
Enter the following code:
    [Shell]
    Command=2
    IconFile=explorer.exe,3
    [Taskbar]
    Command=ToggleDesktop
Now save the file as Show Desktop.scf in the directory C:\WINDOWS\system32.
Navigate to C:\WINDOWS\system32 in Windows Explorer.
Drag the Show Desktop.scf file to your Quick Launch bar
Done - enjoy!
NOTE: This trick does not apply to Windows 7 users. Windows 7 users don't have the "Show Desktop" icon because Windows 7 does not have the Quick Launch bar anymore (by default anyway). Rather, Windows 7 users have a different method that performs the same function as the "Show Desktop" icon (see the very right of your Windows Taskbar if you are on Windows 7).