I've had experience resetting similar toshiba brand laptops, and I agree that the soldered cmos battery is a bit silly. Unfortunately, shorting the cmos battery is not a typical method for resetting the cmos, in fact it may cause some harm. The standard is to use supplied jumpers to break the circuit or to send an erase signal, but neither involve shorting the circuit to the cmos battery. Let's hope no damage was done.
To see if it's something simple like a disconnected video cable, look for an HDD (Hard Drive) indicator/LED on the front panel of the laptop (or may be in a different location, but is generally located on the sides of the paneling). If you see aggressive activity, such as what you'd expect from a boot-up, then chances are a disconnected video cable. If you get no activity, then chances are you aren't getting a successful POST (Power On Self Test); which requires a working BIOS, RAM, Processor, Video output device, and motherboard to connect these devices together. The lack of a successful POST would indicate to look at the required devices for a successful POST, and troubleshoot the most likely candidates first. Let me know if you get hard drive activity or not, and we can go from there.
[Edited for clarity]
I neglected to mention that in this particular case, desoldering the CMOS battery lead (negative) and resoldering the lead back is the only safe method of reset, unless an inset/depressed reset button, that would require a thin object like a paper clip to activate, is present. Such a reset button would be available on the bottom cover/panel, without any disassembly required.
[/edit]
[Edited one last time for good measure]
I should also mention that it's important to pay special attention to the RAM when reinstalling, as you stated you did. It's likely that the RAM is stacked, one on top of the other, correct? If so, try to reseat each module- the less metal you see from the contacts, the better. You should not see half or more of the metal contacts of the RAM modules, as they should be hidden by the DIMM slots. Remember to install each module beginning at about a 45° angle at entry, then applying light, inward pressure on the RAM module as you press it down to a flat position (about 0°). This is a capital offender in most laptops, even ones that have never had their panels removed! (Probably due to shock and/or josseling)
[/edit]
