Experiencing flickering of screen when connecting to a TV via VGA/HDMI

It could be one or the other or both.

My first thought was, the connection built into her laptop that the cable uses to go to the TV may be loose, the pin receptacles may be loose or a bad solder joint of the wires to it.

What is her laptop make/model we can search to see if there have been any reported problems, and ask her gently; Have you dropped it recently?

but has never had a problem before.

Just recently, Just with video in general or hooking up to your TV?

More questions:

• Have you tried a different cable?
• Are you sure you applied the correct driver version? Did you use one from the graphics card manufacturer or from the laptop maker?
• The integrated graphics card (IGC) may not be able to handle both displays, can you try turning off the laptop display while plugged in to your TV?
• The IGC may not handle the TV's resolution or refresh rate, have you checked that? Be careful though, You don't want to go higher than the TV's native settings.
• This might be related either to the refresh rate, or to the detection of the TV screen, and involve Extended Display Identification Data (EDID). HDTV Magazine - View topic - EDID - Extended display identification data
• When connecting my PC to TV it flickers - HDTV - Home-Theatre

See if you can get into the Graphics Properties of the IGC, then Display Devices.
With both screens operating, change the primary screen from Laptop to Digital Television and the laptop to secondary device.
If that works, okay, but you will have to change it back when disengaged from the TV.

This an old, long, thread, but has some good information in it: Connecting a HDTV to a computer - HDTV - Home-Theatre

I could have been more specific instead of general, but I don't know the make/model of your TV, your GF's laptop or if its been dropped.