Yes you can, because they are just hard drive without a magnetic disk and spindle. They all are of same size 2.5", which can easily fit in your laptops HDD housing.
If you've got DVD drive and you feel its not much used then get a DVD SSD Caddy. They come in 2 sizes which depends on your laptop. Bigger one sizes 12.7mm and the smaller sizes 9.5mm. This will allow you to run both the hardisks parallel.
I got Acer 5830TG, loaded with 6gigs of ram, core i5, nvidia GT540m, Samsung EVO 850 120 GB as primary and Seagate 500 GB as secondary.
Samsung EVO 850 is good in R/W performance. This one is a TLC flash equipped. Which can make a write of limit up to 95 TB but in this competition others stops at ~30 TB . At the same time other SSD manufacturers TLC's write speed performance can bring to their knees. They only go up to 30-90mb, hardly to reach the highest peak. But Samsung provides 500+ mb speed performance in R/W both. Which averages to 250mb to 300mb. That's really a great performance as compared to its competitor's in TLC range.
we can push our self to spend extra bucks to get a quality product. :-)