I just bought a GT640 to go in my 'second' Win7 HTPC, and have an odd problem. I'm currently connecting the PC straight into a monitor via VGA (DSUB). This is the only input this monitor has unfortunately. The GT640 has 1 x HDMI, 2 x DVI-D and 1 x VGA on the back. When I connect everything up, more often than not, I don't get any signal to the monitor at all using VGA. I can hear/see the PC booting, but nothing at all on the display. Tried different cables, bypassing the KVM etc, but nothing. I switched back to my old ATI 3650, and that works over VGA every time without problem.
So, is this a known problem, or is there any way round this? Seems a bit excessive to have to buy a new digital monitor just to use the card. I understand that VGA is 'old hat', and likely the GT640 has preference for digital outputs, but the VGA port should still work. I did get a display a couple of times, and everything seemed ok. I then put the HTPC to sleep, and when it resumed, no video again. Reboots/hard power off's also often dont fix the problem.
When it works the display is very good, but I did notice some very faint waves at the edges of windows on the desktop. I certainly don't see anything like this on the 3650 over VGA. That's rock steady.
Probably a bad VGA connector on your GT440 card, especially if the connector is attached via a ribbon cable and IDC connector, these sometimes go bad.
You might consider getting a replacement for the card.