I have an HP Pavilion g7-1075dx running windows 7. The battery will not take a charge and it takes forever to load to windows unless I remove the rechargeable battery.
If the laptop is running on AC power, then the battery status will have no effect on the boot time. If the battery will not take a charge, check it's terminals for any corrosion. Check the same on the laptop itself. If they look clean, then it's likely time to get a new battery, especially if the battery is more than a few months old.
I probably did not state that well. I should have elaborated: The CPU speed can be throttled if the battery is so low or damaged in such a way as to pull the voltage down on the charger. If the charger cannot present the laptop with enough voltage/current, the CPU cannot run at its rated speed. If the OP is seeing a real difference in boot time with and without the battery - then that is my guess as to why.
It would be interesting to see the reboot times (with and without the battery) as measured by the tool in this thread:
If the OP wishes to perform that timed test, I would suggesting letting all services start (even the delayed ones) - then launch the reboot timer tool.