Can you be slightly more specific as to which model it is?
There is a dutch site that you can use to search what type of memory you need (can use) to upgrade nearly any laptop.
I tried the site for you but I found that all toshiba satelite 2800 series are PC100, furthermore some will only let you upgrade by 128MB.
Here is the site you can try it if you want, even if your dutch isn't that good you should be able to find your way through it, dutch is a lot like english. http://www.geheugen.com/memoryzoek.asp
A short guide:
selecteer = select
merk = brand (make)
type = type
Standaard geheugen = standard memory
Maximaal te installeren geheugen = maximum amount memory that can be installed (Including any that cannot be removed)
Aantal uitbreidingssloten = number of expansion slots
If it requires a standard PC133 133-pin SODIMM, then thats what you can stick in. But as Toxicogen said, you should check the specifications to see what its Maximum memory is before you purchase. With notebooks, especially older ones, it is very difficult to figure whether or not they will work in certain instances, so make SURE that wherever you purchase the memory from has a return policy. Other than that, if the notebook requires PC100 and you buy PC133, it should work just fine - so needn't worry about that.
Who's General Failure and why's he reading my disk?