Ubuntu Installation :: Monitor Gives No Signal Message During Install

So my computer works reasonably fast running XP (old 3GHz processor with 512RAM), but every so often it simply freezes. I've tried all I can to fix this, but sometimes when I boot up XP it'll get to the window's logo then freeze, sometimes it'll get all the way to the desktop and then freeze, and sometimes it'll start up, run fine for an hour or two then freeze. By freeze, I mean the screen doesn't update, the keyboard and mouse do nothing. Updating NVIDIA drivers doesn't seem to help - some make it worse! So I've had enough, and decided to download Wubi to try Ubuntu on it. I'm not ready to remove windows just yet (lots of data on this machine) and so I don't really want to try dual-booting yet.

Wubi downloads and runs in Windows fine. When I go to restart, after picking Ubuntu from the menu it shows a little text (I think about installation, and press Esc for menu) then my monitor gives a "No Signal" message. So I try restarting (pressing the button), and pressing Esc to bring up the menu. I tried all 5ish options, and "Safe graphics mode" and "ACPI workarounds" seem to last longer, but the same error occurs, before it has even prompted me (still doing its own thing). So I can get up to GRUB, and even get into the grub> prompt. I tried adding irqpoll and/or all_generic_ide to the boot thing (pressing e in the grub menu), but that hasn't helped. I'm unsure of how to find what hardware my computer has (only computer, don't have receipt), but I know "NVIDIA GeForce 6600 GT".