Mac osx updates

When the hard drive on my beloved Mac OSX 10.4.11 gave up around a year ago I took it to a Mac recommended repairer, who replaced my hard drive. Since then I have been unable to use Safari as the new hard drive was registered to Rosita Mullen rather than my original name Rosina Mullen. Safari doesn't recognise me as the user and although I have tried everything to change my user name and pass word the response is that my pass word on the key chain is not recognised! Subsequently I have had no updates on my Mac since then and I am having problems with this. I have been using Firefox ever since but they are currently advising that my system does not meet their requirements. Help!

How can I get Safari back?
How can I get updates for my software.
How can I get my registration name changed back from rosiTa to rosiNa.

Should I just give in and get a PC?

Wrong.

Why didn't you take it back and get them to make it right?

1. The short name can be easily changed by making a new User Account and moving your files into that. ( You should have a standard account for your day to day use and a Admin Account, this is the Name and Password used for doing updates.)

2. Safari has nothing to do with your User Account name. I'd download a new copy from Apple.com once you are in your new account.

3. Under the Apple Menu > Software Update...

Should you get a PC? hmmm would you know any more about Windows than you know about your Mac?