Installed new memory modules can get to the toshiba post screen

Two ways to approach this.

1. try 1 stick at a time and see if you can boot and the system is working,
2. Download and run memtest to see if you got bad memory.

The symptom is telling you that either the memory you installed is either of the wrong type, incompatible, or is not sitting properly in its socket. Please check your user's manual for the exact type, speed, etc.

If you've added a second module, ensure it is of the correct type, even if it's not of the same size. Some laptops take increments well, eg: You can add a module of 512MB to an existing 1GB module. My Dell Inspiron 9100 does.

Using the same type gives you the double-buffering benefit provided by newer memory modules. A different type memory module may work, but it will not give you the benefit of faster memory access, if it works at all.
Good luck!