Can a Panasonic HDC-SD90 record pc screen via HDMI or AV MULTI Cable? Thanks.
No. The HDMI and AV MULTI Cable ports are output, not input ports. Depending on the OS of your PC, there are programs that capture screen video. Such programs are used by gamers to capture their gameplay.
This link gives some information about recording screen output for Linux: https://fedoraproject.org/wiki/ScreenCasting