Flashing Desktop, on and off

Hi Everyone.

The last week or so, a desktop on one computer(1st) (on a network with multiple computers) begins to flash off and on. The desktop is not responsive at all, however I can open programs like outlook or chrome and use them while behind, the desktop is flashing.

I have found out that if I restart a different computer(2nd) on the network the flashing stops! While the first computer I mentioned is flashing, a third computer(3rd) on the network will have the spinning circle on the mouse pointer, spinning of and on constantly. And again once I restart that network computer(2nd) the flashing on the 1st computer stops and the spinning circle on the 3rd computer stops...That 2nd computer threw a "sihost" error, but I only seen that once.

I have turned off the recommended services listed on other forums, I don't see any of the 3 programs Microsoft has said caused this installed.. And I have done complete virus removals on the computers.. During the scans it found minimal items and nothing too serious.

I am not sure what to do... Every time I think it is fixed the issue comes back. I have been a tech for 10 years or so and never came across anything like this?

If anyone has any insight or solutions please let me know. My clients needs to be up and going correctly.

I think I might have it narrowed down...(Hopefully)


What I have done since I posted my question...


I ended up reformatting the HD and installed a clean windows 10.
Reinstalled the bare minimum software my client needs to operate.
And on Sunday(yesterday) I set up the computer back in their office.


As I was finishing up the set up(getting printers connected and what not) the computer started flashing again!


I thought maybe the issue was because of IP address conflicts, but after checking the router every device add a unique ip via DHCP. There was one device(commercial printer) that had a static ip.. Printer company must have set that up..


There are about 5 computers on the network and this is the only one doing this flashing thing.


Do you think the lan port could be bad?


I am going to connect to the network via wifi and see if that changes anything...


I noticed yesterday, that when I plugged in ethernet cable it took a while to obtain ip address and get internet access...


I have swapped computers at another station in the office and this same computer is flashing at another station! I have a feeling it might be a damaged lan port.. The ethernet cable was pretty tight at the first station, so it could have damaged the port if the computer was pulled out at all...


Let me know what you guys think, thanks again for your help.

So the computer started flashing again.. on wifi.


I guess that ruled out the lan port...


So more details about the network:


We have one computer that acts as a server where all the company files are stored. There are 3 folders under "Documents" that I have shared. On that server computer I have 3 user accounts, one is what the client uses and the other 2 I named network user & network user 2.


So the 3 users on this "server" computer are:


Office (client uses this user to work on computer)
Network User
Network User 2


Out of the 3 folders that are shared, one is shared to "network user"; another one is shared to "network user" & "network user 2" and the 3rd folder is a folder for the owners which is only shared with the Main user account.


Now, on the computer where the desktop is flashing/blinking, I used the "network user" credentials so this employee only has access to one folder. So I have a mapped network drive pointing to that folder.


The other computers on the network are set up the same way, and vary which user credentials they have, depending what they need access to.


No other computer on the network is having issues.


Is there something wrong with the "server" computer that holds all the files? When I restart the "server" computer, the flashing stops on the problem computer.. Very frustrating!