Sounds like things work with the new TV, you just have it set up as a second monitor instead of mirroring the laptop's display. The mouse cursor had probably just moved to the TV display and when you disconnected the HDMI cable that display no longer existed, so the mouse cursor was forced back to the main display.
I will say, however, that using a TV as a monitor is fine on a limited use basis, but unless it's a dedicated HTPC, you're asking for trouble. It might work fine 999 times out of 1,000 but sooner or later something will happen causing the settings to become corrupted or some such and you'll spend a huge amount of time trying to sort it out, probably never succeeding. You're playing with fire here and you've already been burned once, so you should be asking yourself if you're ready to be burned again.
<font face="Arial, sans-serif">My
desktop has W7 HP as the OS and until recently via a VGA splitter I
was able to use a monitor and/or a larger screen TV when working.
This is no longer possible.</font>
<font face="Arial, sans-serif">The
computer is mainly shut down at night and on starting one morning a
small window above the L/S icon stated that the audio system was not
running. On checking I found that sounds would come from the
speakers, I also found that after re-start the window had gone but
still occasionally appears at start-up. I then noticed that sound was
only on one channel.</font>
<font face="Arial, sans-serif">The next
indication was the TV showing that it did not support the input
format.</font>
<font face="Arial, sans-serif">My
computer has sound and VGA ports on the motherboard and VGA and HDMI
ports on a NVIDIA card. I have proved that the splitter and VGA
cables are OK and that there is also no display output from the VGA
port on the motherboard. I had always connected to the VGA port on
the NVIDIA card.</font>
<font face="Arial, sans-serif">I now
have a new Smart TV connected via HDMI but this only shows the
desktop background less icons even when a programme is open. I
haven't setup the HiFi connection yet.</font>
<font face="Arial, sans-serif">I fear
that overcoming these problems might mean a new computer and any
advice from cnet membvers would be most welcome.</font>
<font face="Arial, sans-serif">I just
opened my email site and the mouse pointer had disappeared and after
removing the HDMI cable from the TV it returned,</font>
<font face="Arial, sans-serif">Gerald
Gibbons</font>

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