Windows Defender

[Francis Frost]

We have a fairly new desktop (windows 10 installed) and on switch on it takes a long time to boot and after a while windows defender scans, restarts and scans again continously

 

[Trouble]

Hello and welcome to the forum.

We have a fairly new desktop (windows 10 installed) and on switch on it takes a long time to boot

First of all, how "new" is it. This is not nor should not be the typical behavior of a "new" desktop? Do you have any recourse via warranty from the seller or manufacturer?

after a while windows defender scans, restarts and scans again continously

By "restarts"...... are you saying that Defender stops and restarts or.... your computer restarts?
It sounds like the scheduled task for a background scan has been edited or otherwise corrupted. It's suppose to be only when the machine is idle, unless you've prompted a "scan" (quick, full or custom) through the interface.

When this is going on, do you see any progress? Does it seem to complete? Can you cancel the scan?

Have you maually checked for Windows Updates?
Which version of Windows 10 are you currently running?

 

[Francis Frost]

The desktop is less than 3 years old but out of warrenty.
When switched on it starts to load, the screen shows the date and time and then sometimes it asks for the password. When I try to enter the password I can only enter the first 3 letters before the screen locks , goes blank for a short while then carries on loading until the screen turns blue and the windows defender activates.
If I cancel the scan the computer restarts and the whole process begins again. Likewise if I allow the scan to complete.
My partner ( it is her computer) has informed me that the system sometimes restarts during normal usage,
I can use the F2 button and the BIOS utility is version 2.10.1208 from 2013.

 

[Trouble]

the system sometimes restarts during normal usage

So.... sometimes it does go ahead and boot normally??
A bit confusing because it was sounding a bit like it always did what you were describing earlier.
Try this....

When you get the sign-in screen don't sign-in. Use the power icon on that screen to restart the computer while holding down the shift key, give it a minute and you should see a restart button appear.
That should throw you into the Troubleshooting -> Advanced Troubleshooting screens where you can choose....
Startup settings
To then select #4 ( I believe) to boot the system into Safe Mode.

See if it does the same thing in Safe Mode.

 

[Francis Frost]

The situation seemed to getting worse. I tried your suggestion but could'nt get further than the power icon.
The only action that was consistant was using the F2 facility. My partner, in desperation, enabled everything and the computer booted up normally. We have shut off the sleep timer to Never and so far we are back to normal.
Thanks for your assistance. It taught us that patience is also a virtue with computing.

 

[Francis Frost]

Spoke too soon. Swiched on the computer yesterday morning after it installed the latest update. Same problem as before. I see we are not the only ones to have problems after an update. Any ides please.

 

[DarwinJones]

This is also my problem in windows 10, so I decided to go back to 8. I have it fix for a while but it goes back the other day.