NVIDIA Geforce2 MX 400: Tv-Out 'fantastic' problem , Ideas pls!

Hello, I'm using an old Geforce2 MX 400 card with TV-OUT for watching movies
on my TV. I'm using the program TVTool , my TV-Chip on the videocard is
CH7007 ...
Everything is ok when I press 'TV Mode' button in my TVTool program: I
have the picture from the monitor on TV (Dual-View), Pal -format, 800x600
resolution .
What I don't understand is: why on my TV there do appear some horizontal
lines (appearing and dissappearing, flickering or glimmering?)
I have to describe what I see: everything is ok (in the movie for example)
till a blue picture appears, or on my windows blue screen: if the screen is
blue then those flickering horizontal lines are red... and if the screen is
red/pink/yellow then those lines are blue ... I thought this is something
normal and I was allready used this month watching the movies this way and
I didn't even pay attention to all this (red/blue flickering lines on
blue/red picture)... Until something happend this night: I pressed 'TV Mode'
button AND on my windows blue scrren I saw no lines on the TV: I was
surprised, this
happend for the first time... then I noticed that I forgot to close my
antivirus program... so I thought: could this be because of that
window(antivirus running) which I left opened? I was surprised when I was
looking on
my TV screen, exercising and trying something new: and I finally understood
what was happening: if the antivirus is scanning then there is no red/blue
lines on the blue/red screen, but on I press pause in the antivirus or close
this program those (disturbing) lines appear again: red/blue lines on the
blue/red screen ... I wanted to try something new: I did the same to other
program, I ran an anti-trojan and: the moment when I press scan, I want to
see what happens, I minimize the program and look on the TV screen:
absolutely no problem, the picture is clear as much as it can be, no
flickering lines, the colours are perfect when I play a movie, no red
horizontal lines on the blue screen, no problems of any kind... but the
moment I pause or stop the scanning of hard drives (or close this
anti-trojan or anti-virus program) the red lines appear again on my windows
desktop blue screen or in the movies I play...
I cant't find an explanation for this! Maybe you have any ideas?
What does that TV-Tool program have in common with an anti-virus or an
anti-trojan program? Why if I press 'scan' in such kind of program (scaning
my hard-drives) then there are absolutely no problems with the picture, it
is as perfect as it can be! Why the moment I press 'pause' or 'stop scan'
in my program or close this anti-virus then those red lines on my blue
screen appear again?
Is there an explanation for this fenomenon? Can you help me understand the
truth? For now I am very confused and don't even know what to think of. I
would appreciate if you would come with any idea, doesn't matter how strange
it is, but I need any explanation you have no matter how 'paranormal' it
would seem.
Thank you in advance.