I am preparing a laptop for sale. Instead of wiping the whole drive, I just want to delete the personal information I have. I have an ssd by the way with TRIM support so even if I delete the files they shouldn't be accessed (I think)
For Window 7: If I just delete the user account (and choosing the option to delete all the files), should I be fine
For Linux Mint: If I type in the command
sudo deluser -force -remove-all-files -remove-home myUsername
should I be fine?
No, you should not be fine. That data, even though "deleted" is not actually deleted. You should go through the trouble making sure the SSD is sanitized before selling the computer. TRIM should not be considered to be a "safe" method of cleaning. A recent study was done by the University of California in San Diego with some great info on sanitizing both SSD and HDD and is worth the read.
The command
sudo deluser --force --remove-all-files myUsername
should be enough as --remove-home will have no effect with --remove-all-files as this removes already everything. Be sure that there are no files relevant to you owned by other users e.g. root
In Linux, if you are sure you have deleted all personal data, you could use the zerofree tool to zero all free blocks on the file system. You should probably use -f 0xFF to erase the free blocks to 0xFF which on the SSD then should trigger the block erase by the firmware.
Probably a similar tool exists for Windows but I do not know anything about that beast.
shredthe home files, that should make a trivial undelete harder... but I've read that SSD's (really any flash type storage) can sometimes move blocks around, into or out of it's spare blocks (or something like that?) so you're never really sure if a piece of old data is really deleted or not