Never Ending log off screen

[Xylems]

HELP!!!

OS: Windows 7 Proffesional
Bit: 64
Ram: 2G
HD: 250Gb
NIC: 1Gb
(All computers have these specs)

Here is the issue:

Someone at work just came in because he had a task that would never end. I tried killing the process and nothing happened. Afterwards we tried to log off and back on and we got the never ending logging of screen. He has an issue that I have been having as well. When he tried to upload some pictures to the our Shared network drive the process would infinitely calculate and then not respond. Then the entire process hangs and trying to restart also gets a never ending log off screen. I tried to upload some pictures from my phone to the Network Share drive and the same thing happened to me a few days ago. Since we did not use to have this problem I figured it could have been the AV upgrade so I tried to disable the AV and still same thing happened. I tried to replicate the problem on another co-workers computer also running same OS and his worked just fine.
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please let me know how to fix this or what i should look into.

 

[DeanP]

I would check your computer for malware and check for corrupt OS files....

Run sfc/ scannow in elevated Command Prompt (right click on Command Prompt and click on run as administrator)

Get rid of your current anti-virus.
Download Malwarebytes and download Microsoft Security Essentials.

Malwarebytes - Malwarebytes
Microsoft Security Essentials - http://www.microsoft.com/security_essentials/

Run Malwarebytes few full scans in Safe Mode WITH networking.
Run Microsoft Security Essentials few full scans in normal mode.