When is the last time you accessed it? I don’t think they last forever.
Hotmail used to cancel accounts with no activity for 30 days. I know there’s some kind of new Hotmail, fits in with their free version of Outlook, but that’s all I remember. Sorry.
Yahoo eventually started having a time bomb also, but it took months. I gave up on the latter because they have literally no spam filtering at all, and I got sick of having to delete literally 5000 to 6000 messages each time I went into one my my mailboxes.
The Hotmail/Outlook Login Page
Click on the Can't Access Your Account link for options, which includes password recovery, ect.
Microsoft will suspend inactive accounts after 90 days. They delete inactive accounts after 12 months. Hotmail is old news. Microsoft now has “outlook.com” based on their Office 365 products. Not sure why you wouldn’t be able to get into your old account unless it’s been a long time since you’ve accessed.
If you have the username/password, try another email client (or go to the Web site to try to access). That will tell you if the problem is Outlook or some other issue.