will only boot in Low Graphics Mode

Hi this means the wifi doesn't work and I cant get online.
Ive tried restarting

the message on start up reads,

The system is running in low graphics mode
Your screen, graphics card and input device settings could not be detected correctly, You will need to configure these yourself.

it boots fine in default graphics mode but cant use wifi *update last time I restarted the mouse wasnt visible so I couldnt boot

luckily I just bought a raspberry Pi so can still access the web

thanks in advance for any help

I did an update and upgrade recently and it said something was missing and I had to do something but being a noob I didnt know what to do
not sure if Ive restarted since then, so that may be the problem?