.mp4s are now listed as invalid

MPC-HC (Nightly)
----------------

Build information:
Version: 1.7.13.32 (219e087ec0)
Compiler: (SSE2)
Build date: Aug 18 2017

LAV Filters:
LAV Splitter:
LAV Video: 0.70.2.17
LAV Audio: 0.70.2.17
FFmpeg compiler: MinGW-w64 GCC 7.2.0

Operating system:
Name: Windows NT 5.1 (build 2600, Service Pack 3)
Version: 5.1

Hardware:
CPU: Intel(R) Pentium(R) 4 CPU 2.80GHz
GPU: Intel(R) 82865G Graphics Controller (driver version: 6.14.10.4396)

I have been watching videos with MPC for a long time and now today, all my videos are listed invalid when I try to watch, the music mp3s play fine.

win xp 32bit fully updated, not pos ready,

problem solved, uninstalled and reinstalled klite and problem went away, I had installed a video joiner program which must have screwed with the registry, thanks