Disable Windows Defender and make certain it is not running before doing the following;
Run the PurityScan uninstaller.
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Download CCleaner and install, then run it. Uncheck "Cookies" under "Internet Explorer".
Click on Run Cleaner in the lower right-hand corner. This can take quite a while to run.
Close when finished.
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Please download the trial version of Ewido anti-malware here:
http://www.ewido.net/en/download/
Install it, and update the definitions to the newest files. Do NOT run a scan yet.
Next, please reboot your computer in Safe Mode by doing the following:
1) Restart your computer
2) After hearing your computer beep once during startup, but before the Windows icon appears, press F8.
3) Instead of Windows loading as normal, a menu should appear
4) Select the first option, to run Windows in Safe Mode.
For additional help in booting into Safe Mode, see the following site:
http://www.pchell.com/support/safemode.shtml
Once in Safe Mode, please run Ewido, and do a full scan. During the scan it will prompt you to clean files, click OK.
Save the logfile from the scan. Restart your computer in normal mode and please post a new HijackThis log, as well as the log from the Ewido scan.