The c660d appeared about 9 years ago, and probably had Windows 7 when it was new.
The first thing to work out is what software you need to run.
The FH software I use is Windows-only. Do you keep your data locally?
If you only use, say, Ancestry to build your tree, then anything with a browser will do. It could run Windows, Linux, MacOS, Chrome or Android.
Do you accumulate loads of photos? Audio files? Videos? You will need enough storage space to at least duplicate what you are using at present. Most current laptops will have a hard drive larger that what was available in 2010, though there are some with VERY small drives - 64GB or less. Windows+Office will take about half that. Yes, you can add an external drive, but that should be for backups, not for everyday use.
Does the keyboard fit your needs? I think you need a proper keyboard for family history; pecking away at something onscreen is not fast enough.
Is the screen large enough? The Tosh usually had a 15.6" diagonal screen, with 1366 x 768 pixels. Luckily, with TVs sharing the technology, high resolution screens are more common now. Most of us have poorer eyesight now than we did in 2010, so make sure you can see stuff on the screen.
There has been a fashion recently to ship laptops without a DVD drive. If you regularly use CDs or DVDs, you might need to budget for an external USB unit.
If you have the option, look out for a solid state hard drive. These improve disk speed hugely, use less power and are pretty much immune from physical shocks. My current laptop is also from 2010, but runs about twice as fast as recent one, mostly because of the solid state drive.