Hello Lena,
If all of your email is still showing up in Hotmail/outlook then you are safe to uninstall Incredimail. However you should first export all of the mail by following this guide here. You can then choose to use another email client such as Mozilla Thunderbird or stick with Hotmail/Outlook.
Uninstall I would first remove Incredimail and then Flash player.
I hope that helps you, let us know how it goes or if you have any issues.