My memory's SODIMM

Yikes. I have resurrected my spouse's Toshiba S3000-X4 laptop, and with a little tuning it is usable on XP Home SP3. Don't laugh, it has 128 mb memory. I've upped the Virtual storage to 1 gb, but it is still sluggish at times especially startup, where it takes around 5 mins. So, I think I'll have to lash out on some memory. So I've read all about it, and I'm confused.

The laptop has 2 slots, and the max is stated as 2 x 256, which is better than what I have now. The slots are SDRAM SODIMM 144 pin PC 100. Now can or will any SODIMM 144 pin memory fit, or do I have to go for the very expensive Toshiba component? There are lots of memory around with this basic spec that look the same, but not with the Toshiba part number.

Would 512's be a waste of time, why can't I fit say 1 gb chips? Is there an addressable limit in the old pc?

As you can see I do not read memory manuals at night.

Have a look at Crucial System Scanner tool:

http://www.crucial.com

It will tell you what type of RAM the system has and the upgrade path.

Make sure you have the correct speed {or better}, and it will work . Make sure you match the ram chips {the same}. Anything more than 2x256 is a waste of money because of the processor. Being lazy, when I work on old laptops I use pc133 which has worked on all so far.