|"The receiver has Scart output which is converted to phono audio and video plugs."|
The correct term is RCA plugs - a phono audio connection is only one of the things that type of plug (or jack) is used for.
"Does S-Video work in as well as out?"
If your laptop model has S-Video capability, it's video out, only. You use a standard S-Video to RCA adapter in the "S-Video" jack. On a laptop, the "S-Video" jack, or whatever they call it, often is not a legacy S-Video jack - it has more than the 4 pin holes required for a legacy S-Video connection, but the jack is compatible with using a standard adapter in it (S-Video male 4 pin to RCA female). Most if not all laptops have no built capability of accepting video in, but you can get adapters than will accept video in, e.g. USB ones.
A (legacy) S-Video connection or legacy composite video (one RCA ) connection has a legacy standard TV output, which is ancient and primitive, yielding you relatively crappy looking video in comparison to computer monitor video. Video from a computer is kinda okay, but your Windows screens do not look as good as on a computer monitor - e.g. the fonts often look crappy.
If your receiver has HDTV output (three RCA connections for the video) you may be able to get an adapter that will accept input from that - that will look much better than S-Video video or legacy composite video.
Neither has audio capability.
The audio you can connect via a dual RCA to 1/8" shaft stereo plug adapter to an audio in jack on the laptop, but most if not all laptops don't have that (it may work okay in the mic jack, it may not), or an adapter that accepts HDTV input should have a jack for that.
If your receiver has HDMI output, that also supports audio output - you would need an adapter that supports HDMI input. HDMI cables are relatively expensive. That will look much better than S-Video or legacy composite video and HDTV video.