Windows 10 PC hijacked

I have a Windows 10 PC which I have just updated to the latest Windows 10 Insider Preview Build 1709 (OS Build 17074-1002). I now find my PC is haunted with hijacked web pages, unwanted ads, videos, music, etc. I never know where I am going to be misdirected and some sites I cannot access at all without being diverted. Ironically one site I cannot access is Experts Exchange without my PC going off in some adventure of its own.
I have done antivirus scans using Windows Defender and AVG Internet Security Suite. Defender did find some viruses which it dealt with but my problems remain the same. Can anyone suggest a way forward?
I did try to uninstall the latest Windows 10 update but could not do that either, screenshot attached.
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JohnBusiness Consultant (Owner)Commented:
It is not a Windows 10 Update issue (for certain). Windows Defender got stronger.

Restart the computer and run Windows Defender again - Full Scan.  Follow that with Malwarebytes and then try restarting again.

See if that removes the viruses (which is the issue - not Windows).

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medcomputersAuthor Commented:
Thanks for your advice John, I will do as you say. I didn't think it was anything to do with Windows Update.
RaminTechnical AdvisorCommented:
Please try AdwCleaner to remove any adware from your PC.

Did you try System Restore the same as below steps ?

Open the Start menu and click on the Power button.
 Then, while keeping the Shift key pressed, click on Restart.
 click on Power, press and hold Shift and then click Restart.
 Then, Windows 10 reboots and asks you to select an option. Choose Troubleshoot.
 Then, on the Troubleshoot screen, select Advanced options.
 On the Advanced options screen, choose System Restore, select a date prior to this issue.
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i have updated several pc's - never had such problem.
Was this also happening before the update?
and just post the screenshots plse - not in a doc (not needed)
Hello ThereSystem AdministratorCommented:
You do not know where the malware is, so I'd enter Safe mode with minimum requirements and run all possible scans. I'd start with Malwarebytes and if this will not find anything I would continue with very effective and my favourite Farbar Recovery Scan Tool and RogueKiller (still in Safe Mode).
Yes, it will take some time but it's worth. Malware can be spread in multiple location on your computer so you need to check the whole computer, not only a specific location.

You probably know that the last option is to reinstall your OS. But first, run what I suggest. It usually finds a junk and removes it.

1. If possible, disconnect from the Internet.
2. Enter the Safe Mode and run Disc Cleanup or anything that deletes all your temp files.
3. Still in Safe Mode... run all necessary scans. Deep scans!
Some free tools: Kaspersky TDSSKiller for removing rootkits, Malwarebytes and HitmanPro for removing malware, AdwCleaner for removing adware.
4. Try to remove all 'unknown publisher' apps as well as recently downloaded files. Also delete all browsers add-ins.
5. If this doesn't help, try to go back in time using System Restore.
6. If nothing helps, you should consider reinstalling your OS.
Good luck!
medcomputersAuthor Commented:
Hi I carried out John Hurt's suggestion and it seems to have worked first time, many thanks. I have taken note of all the other suggestions especially that from Hello There which I will work through should the problem return.
I am not sure about the comment by nobus comments regarding not posting screenshots in a Word doc. I have always saved my screenshots in that way in order to save them. Should I just save them as .png? I have just tried saving this comment  and did not realise you could save file as .png.

Thank you

no - use the snipping tool, and post them as is (png i believe)
medcomputersAuthor Commented:
Thank you everyone for all your suggestions.
JohnBusiness Consultant (Owner)Commented:
You are very welcome and I was happy to help.
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