I'm having a problem hooking up my nintendo. Everytime I turn it on the screen just flashes white then black then white and so on.
Now I thought of stealing the cords and stuff from my friend incase it was that, But when we hooked his up, it did the same thing.

Any Nintendo in particular? And how does it connect? SCART? Composite? Aerial cable?

Have you tired setting a surtain channel for it? AV? channel 6?

Have you tried blowing down it? (cleaning) or/and the cartrage/CD?

If it's using an RF cable then pick a channel and tune it, or of the remote has a 'c' button, press it then '36'. This is the 'channel' (not the same as a TV channel) that most consoles are preset to use.

If it uses composite or SCART try selecting one of the AV channels.

Are you putting it through a video recorder or straight to the TV? Video recorders sometimes have a test mode which displays patterns on the screen, that could explain it.

Straight to the TV.

I'm using a ac adapter and an rf switch?
I'm sure it's just the original cords I got it with.

Have you tried different games? Have you tried blowing into the game cartridge? Blowing into the console? Does the power light flash as well?

none of my games work. I've tried the blowing thing, but it doesnt change anything.

The power light flashes, strangley enough it flashes the same time as the game when the games do show up.