sorry to post to an old (not that old)thread but i thought i'd add my two pence worth
I've got the LE37R8 Samsung tv and it does the same thing ,its VERY ,VERY picky bout what it shows on vga,it wont show my 360 on vga at all it goes into stanby if i plug the cable in my 360 with it not even ON!!!
I tried for fecking ages to find a vga lead to show my htpc on the lcd and after 5 cables all different makes it worked!!
Sooooooo,,,anyway the reason im posting other than to share my experiences is this,I rang Samsung tech support up the other day about 360 not showing on vga,it was my 2nd vga 360 cable and it works in vga on every monitor i got.
I explained the problem to the guy and he said a repair engineer will call me back??.
Not go to tv try this, reset that,oh it must be the cable like i've had in the past,no .
straight away when i said 360 on vga he said an engineer will be round,pronto?
He would not say anything else on the matter but said "It sounds like a fault"which they never say,EVER.
so if you got a problem with 360 on vga with any new samsung tv ring um, i think they got some problems with there TV's
P.S Engineer due wed 27/2/08 will post results if anyone wants.