Windows behaviour in PT11.3.1

[martinaston]

The transport bar specifically, but other windows (plug-ins, dialogues etc.) all are exhibiting strange behaviour when moved around within pro-tools, i.e they seem to lose focus and disappear behind the main window when moved even at very slow speed.

I have done extensive virus/malware checks but nothing showing up from Avast!, Malwarebytes, Superantispyware. I have also run Winthruster to detect registry errors, system is clean.

The problem only affects pro tools (11.3.1), other apps running on the PC do not malfunction.

Windows 7 Home Premium SP1

Intel Core(TM)2 Quad CPU Q9650 @3.00GHz

8.00GB
64bit

Any remedies Doctor?