PS3 Multi-Out Problems

My girlfriend got a PS3 at Christmas, we tried it out on my TV which is a 17inch Widescreen with no HDMI cable. We connected it with the PS3 Multi-output cables (Red, Yellow and White) and it worked fine. At hers, she uses a HDMI cable.

We're back at mine now and the multi-out cable refuses to work with any of the TVs in my house (my 17inch and the 32inch downstairs). It works with the HDMI downstairs but the multi-out hasn't worked at all. We've tried using a Scart, and different multi-outs from the PS2 as well but it's not showing up. Has anyone else had this problem?

Edit: Also, how do I fix it :P

Turn your Ps3 off. Hold down the power button on the console for 5 seconds. Should reset it back to normal.Randoggy

This is the correct answer.