Get to know the startup, processes, BHO, DLL in your PC

Note: This is a revised copy. I deleted the original post as it contains outdated links. Thanks!

Find out if the files, processes, BHO, startups, DLL, Event ID and Windows Services are safe or not.

Scan your event log, monitor processes and services in your computer.
Below are services and tools that will help you managing those items.
Note: Post in forums if you have questions on file or contribute by submitting file info to below websites.

Altair Technologies
* EventID.net - If you want to investigate the caused or description of Event ID that you are seeing in Windows Event Log Viewer, use EventID.net which has the growing list of Event ID database.

Bleeping Computer
1. Startup Programs Database
2. F0, F1, F2, F3 HijackThis entries
3. O4 HijackThis Entries
4. O20 HijackThis Entries
5. O21 HijackThis Entries
6. O22 HijackThis Entries
7. O23 HijackThis Entries

GFI
* EventLogScan - Scan your pc for high security events with GFI's free online service - EventLogScan will install an ActiveX control on your machine and analyse all the events in your security event log. After the analysis, it will present you with an HTML report with all the critical, high and medium security events found and a brief explanation of each. To perform the scan, you must download the ActiveX control to your machine. You will be prompted to download the GFI EventLogScan Service ActiveX Control. Select "Yes" to download and start the test.

Microsoft
* Microsoft's DLL Help - database contains information about DLL files that are included with selected Microsoft products.

Senior Mag
* Computer File Extensions - Find computer file extensions - browse alphabetically.

SpywareData
1. BHO List
2. Toolbar List
3. LSP List
4. ActiveX List
5. StartUp List

Sysinfo.org
1. CLSID List and Startup Info
2. Startup Applications List
3. CLSID or Browser Helper Object list

Tools:

BillP Studios

* WinPatrol Free - Monitor vulnerable areas of your computer or get alerts about new programs. WinPatrol will monitor Startup Programs, IE Helpers, Scheduled Tasks, Services in Windows, Cookies, File Types and Hidden Files. It will also list your Active Tasks and you can use it's newes feature "Delayed Start" to increase speed of your computer startup by delaying programs not needed immediately.
Note: BillP also offer WinPatrol PLUS. See what's in PLUS version here.

Javacool Software
* SpywareBlaster - Not only it protects your computer from known bad spyware and activeX, it also include a "find tool" to help you see whether a file is indeed known bad. Note: The said "Find" option is available only if you will enable any protections it offer. Screenshot at http://www.dozleng.com/images/blog/sbfind.jpg

Malwarebytes
* StartUpLite – A program that requires no installation! Just download and run this application and it will try to detect if Windows is starting with unnecessary start-up applications.

Patrick Kolla
1. Spybot Search & Destroy - This popular antispyware scanner also includes Startup List that will allow you to manage your startup items. See http://www.spybot.info/en/howto/startup.html
2. RunAlyzer - RunAlyzer is our brand-new autostart & configuration manager that allows you to view and edit all the spots where Windows looks for programs or services to start. It's a combination of a standard configuration manager and an advanced tool to locate and remove places where hijackers, spyware and other malware hide.
Note: At the time of this post entry, RunAlyzer is currently in BETA status. Use at your own risk.