Download Ad-aware from here: http://www.lavasoftusa.com/software/adaware
Install by double-clicking on the downloaded file.
After installing but before running, update Ad-aware by using its Globe icon.
After updating, shutdown and restart Ad-aware.
Ad-aware is ready to scan and clean your system following these steps:

Under Ad-aware 6 > Settings (Gear at the top) > Tweaks > Scanning Engine:
"Unload recognized processes during scanning."
Under Ad-aware 6 > Settings (Gear at the top) > Tweaks > Cleaning Engine:
"Let Windows remove files in use after reboot."
Press "Scan Now"
Check option "Use Custom scanning options"
Check option "Activate In-Depth Scan"
Press "Select drives\folders to scan"
Select the active partition which is usually C:
Press "Next" to let Ad-aware scan your drives...
If it finds "bad" files and registry keys, press "Next" again
Right-click in that pane and choose "select all"
Press "next"
When it asks to remove all checked items, Press "OK"
Close Ad-aware, reboot your system.