Probably a malware issue. Start with running this procedure and post the logs.
Please download Malwarebytes' Anti-Malware from here or here and save it to your desktop.
Double-click mbam-setup.exe and follow the prompts to install the program.
At the end, be sure a checkmark is placed next to
Update Malwarebytes' Anti-Malware
and Launch Malwarebytes' Anti-Malware
then click Finish.
If an update is found, it will download and install the latest version. Please keep updating until it says you have the latest version.
Once the program has loaded, select Perform quick scan, then click Scan.
When the scan is complete, click OK, then Show Results to view the results.
Be sure that everything is checked, and click Remove Selected.
A log will be saved automatically which you can access by clicking on the Logs tab within Malwarebytes' Anti-Malware
If you continue to experience problems after doing this, please post a HijackThis log by doing the following:
Download the HijackThis installer from here.
Run the installer and choose Install, indicating that you accept the licence agreement. The installer will place a shortcut on your desktop and launch HijackThis.
Click Do a system scan and save a logfile
Most of what HijackThis lists will be harmless or even essential, don't fix anything yet.
Post the logfile that HijackThis produces along with the Malwarebytes Anti-Malware log
