Some people may be a bit confused about what qualifies a computer to be called a snail.
Bob Rankin has a nice amusing little checklist to see if your computer qualifies.
If you answer 'Yes' to anything on his list, but your computer is still usable for normal purposes (web browsing, email, word processing, etc), with recently written software...then you have a snail.
If it's too old to run any recently written software, you have an antique. That is a different class of PC, than snail.
And be sure to read on, because following his checklist, there are some good tips for getting more out of your computer, no matter what its age may be.