Sorry, this is too vague.
I assume you want WinSCP to do something automatically. Do you have that part done already? If you have, I do not see, how can you have problem with logging in automatically.
So how are you using WinSCP? Do you use scripting? Or are you using some operation started from command-line, like /keepuptodate?

I have a weather station the software 'Cumulus' and 'Weatherlink' uploads data to a website every 4 minutes.
Unfortunately they don't support SFTP which my provider now requires.
I am hoping to use WinSCP to upload the data via SFTP. My problem is the Windows computer I am using is affected by Widows updates so every now and again it reboots due to an update.
How can I get WinSCP which will have automatically started along with the weather software to auto password log in to the remote site.