Laptop will not boot after I reseated the battery

I have a Toshiba Satellite A25-S307 that was given to me without a hard drive in it. I purchased a WD 600VE Hard Drive for it and put it into the machine. I do not have the original HDD bracket or holder for this machine. My purpose was to make sure that everything would work and to load an operating system onto the Hard Drive in preparation for future portability. I loaded Windows XP-Pro and worked my way through all of Toshiba’s applicable drivers and updates. The machine was running fine. I loaded Microsoft Office, still no problem. I loaded a DVD viewing program and it loaded DirectX9 as a part of its process. I was in contact with a local service center about obtaining a HDD bracket while this last program was loading. I noted no problems. The service tech indicated that I needed to look in the battery compartment for a stamped letter to indicate what bracket was designed for my machine. I shut down the laptop, unplugged the AC power, and removed the battery. We never did find the stamping he was requesting. After my conversation with him I reinstalled the battery, turned the machine on and answered a call, (I was at work at the time.) I started to proceed with my configuration of software when I realized that the touchpad was none responsive. The keyboard was also nonresponsive. I gave it a minute after clicking the touchpad keys and I depressed the space bar a couple of times. I though maybe it had gone to sleep. No response. I attempted to eject the CD in the DVD drive to no effect. So I then held down the power button for a few seconds until the machine powered down. I unplugged the AC power and removed the battery for 30 seconds. I then reinstalled the battery and the AC power to reboot the machine. I turned on the power and got a green power indicator light as well as a green AC power supply light. The battery light was amber but it will take a charge and was green during the OS loading procedure. The machine will not boot. The fan will come on initially and then turn off after a few seconds. I have checked the new hard drive to make sure that it was seated. I have checked the processor to assure that it was seated. I have tried to boot the machine with/out the HDD but get the same result. Can you help me? I can’t find a parts listing or service manual anywhere. I had and have great hopes for this machine. I even had the wireless LAN up and running. The people across the alley apparently do not have their Wireless network secured I do work on desk top computers and networks as a side job but this is my first laptop. Help?

Here is a Toshiba Satellite A20 laptop disassembly guide. It should be the same as for Satellite A25. You can find the hard drive holder for your laptop on the internet, just search by the part number:
P000368190 – hard drive holder for laptops with letter “C” in the battery bay
P000377210 – hard drive holder for laptops with letter “P” in the battery bay
It is hard to say why your laptop doesn’t boot anymore. I think it is not connected to reseating the battery, it’s just a coincidence. It is possible that you have a loose connection somewhere inside the laptop.

When I have an unknown problem I minimize the system as much as I can. It is possible that you have a loose connection somewhere inside the laptop, some cable isn’t seated properly. Try to remove all devices that you can access from the laptop bottom – battery, hard drive, modem, DVD drive. Try to turn on the laptop after each removed device. If it doesn’t help, then you’ll have to go inside (if you feel comfortable of course). Try to move the memory module from one slot to another. If you have 2 modules installed, remove them one by one. Remove the wireless card. Try to reseat all connections you can access. Just in case check the AC adapter voltage, make sure that it works fine. There is no straight answer for your problem. I’ve fixed a lot of laptops simply by reseating connections. Try it first.