IMPORTANT: If you are not familiar in using the provided tools in the said guide, don't do it yourself. Seek help in HijackThis forums.
It is important that you run HijackThis.exe in its own folder so the backup files that HijackThis creates will not be accidentally deleted.
Open 'My Computer', then double-click to open C:\ (or the drive letter that your Windows is installed on)
In the menu bar, click File-->New-->Folder.
That will create a folder named New Folder, which you can rename to ''HJT'' or ''HijackThis''. Now you have C:\HJT\ or C:\HijackThis\ folder. Put your HijackThis.exe there, and double click to run it.
Click 'Scan' button. Click 'Save log' button. Save the 'hijackthis.log' in your desktop. Copy and paste the content of 'hijackthis.log' and post the log file in any forums that offers HijackThis analysis.
You can find the forums that offers HijackThis analysis in http://a-sap.info