GM45 is a rather new chipset, this is probably a kernel driver issue and you need to be running a very current 2.6 Kernel to get support for that chipset..
Install from Debian Lenny CD-1, rather than the netinstall, then download and update to the latest 2.6 Kernel and see where you end up..
You will probably need to download and compile the latest intellinuxgraphcs driver and possible the e1000e driver.
There appears to still be issues with the Graphics Drivers for this chip set.
http://www.gossamer-threads.com/list.../kernel/984797
Also beware if your NIC requires the e1000e Driver as a bug in the driver has been found to Trash the NVM/eeprom on that NIC rendering the NIC useless.
http://marc.info/?t=122038337000003&r=1&w=2 I can't tell if this is limited to the 2.6.27 kernels or if older kernels may be affected as well. heres a thread from the IBM Thinkpad forum discussing this issue with a beta kernel in Ubuntu..
http://forum.thinkpads.com/viewtopic...1dbdf2a2d9a697
Isn't new hardware FUN !!