Can't fix, uninstall or reinstall as can't find avgsysx.dll

Hello Simon,
We regret for the inconvenience caused. We would request you to know whether you are trying to install AVG free or a paid version and also mention your product name to assist further.
Thank you.

Help please - my mother-in-laws laptop (vista) keep showing the error message that avgsysx.dll can't be found.
I can't fix, reinstall or uninstall as I keep being told that there is a error.
I was being helped by the "chat" system but for some reason the remote control software wouldn't work and me with fat thumbs accidentally closed the chat tab! Really sorry to the patient person at the other end - I wasn't being rude, honest, just fat thumbs!

Can somebody help please as the laptop is virtually useless as the fault window keep popping up and my m-i-l can't cope!

Hello Simon,
We regret for the inconvenience caused. We would request you to know whether you are trying to install AVG free or a paid version and also mention your product name to assist further.
Thank you.