About the only suggestion that I can make, is to go into the Startup tab of msconfig, and disable everything that you find there and try rebooting to see if it effects the start time. If so, then go back and reenable the items one at a time and rebooting to see when the delay returns. That would be the culprit to deal with. There are some startup items not found in msconfig, and you might try using StartupCPL to disable them.
EDIT: If the above doesn't help, then it is likely that the problem is a driver
. That takes more time and thought to locate. You might also check the services.msc to see if there is anything there that should be disabled.