The laptop in question is the Acer Aspire 1644WLMi, dating from 2005.
My guess is that it's too old to take any SSD upgrade, but hopefully someone will prove me wrong!
I'm very comfortable with old hardware and my trusty 1644 likes running Ubuntu, if a little more slowly than I'm use to.
Spec. is Pentium M 760 processor, 1GB DDR2, 100GB HDD.
That HDD is a Toshiba MK1031GAS, which has a 40-pin ATA-6 interface.
If I could find a compatible SSD, I would give the upgrade a try.
If not, is there a faster HDD available?