Make a new folder to put your HijackThis.exe into.
(Anywhere on your hard drive is fine other than your Desktop or the Temp folder. Suitable examples are:
but feel free to use any name.)
Extract and save the HijackThis download to the new folder you made. Then navigate to it and run HijackThis from there. (This is to ensure it makes the necessary backups for recovery if fixes are made) Then, doubleclick HijackThis.exe, and click Scan.
When the scan is finished, the "Scan" button will change into a "Save Log" button. Press that and copy & paste its contents in your reply. Most of what it lists will be harmless or even essential, don't try to fix anything yourself.