What type or size flash drive

[patmich]

Need to backup my computer on a flashdrive before purchasing a new computer.  What type and size drive do I need?

[Prométhée]

Hello
for the type, it is depending on what you find most suitable for your use, a simple external USB hard drive, not suitable
For the size, it all depends on the space you need for the backup.
How much data is saved?
If for example you have 500 GB of photos / videos, music, you need an external hard drive of more than 500 GB!

[WAWood]

@patmich 

You also need to be made aware that you can't "back up your computer" properly by simply copying files and folders to an external medium.  All that will accomplish successfully, is backing up your personal files and folders.  It will not back up any settings or applications.  But, if personal files are all you want, then that will work.

If you want to also back up settings, but not applications, then look online for CloneApp -- as it is the best freeware app out there for backing up settings.

If you also wanted to back up applications, that poses serious issues.  First, you can't co that properly without commercial software, all of which cost money, and most of which will not run on WinXP anymore.  Second, none of your apps are going to work on Win10 as they are too old.  So even if you spend the money to back them up and restore them to a new PC, that is basically wasting your money.

You would really need to hunt online for new versions of your applications to install on a new PC.