flashing n7000


Hi
I am trying to remove a viruson this customers phone. I have previously downloaded the "latest version". I have reset the phone,both data and cache. When I try to update firmware the process always fails at the same point. I have also reinsstaled the drivers after a windows search. Can some one please suggest what I am doing wrong? I experience a very similiar problem when I try to unlock S6 models as well. I am assuming my drivers are wrong somewhere. It seems that my pc cannot find the phone after reset?
Chimera Mobile Phone Utility version: 9.86.1551 @ 2016-04-15

Printing phone history

SW Change
15/04/2016
11:48:58

SW Change
15/04/2016
11:39:02

SW Change
15/04/2016
11:24:56

Reset Reactivation Lock
06/04/2016
11:08:50

Reset Reactivation Lock
06/04/2016
10:40:21

[Firmware update started.]

Extracting firmware…
Unzipping firmware: N7000XXLT9_N7000XXLT3_N7000OXXLT3_HOME.tar.md5.

Processing firmware…

Flashing firmware…
Waiting for download mode.
Connecting.
Reading PIT.
Flashing cache.img
Flash firmware failed.
Finished at local time: [04.15.16 13:17:04]
WorkID: 10327727

Thank you for any help
Steve