Three credit bureaus won't allow me to view my credit report?

I just turned 18 and I tried to open a checking account with HSBC. However, to verify my identity they asked me a particularly odd question,about a mortgage taken out in April 2008. They asked me to name the account provider and amount paid. I became curious,and decided to perform a credit check. When I filled out the application they too asked me the same question, when I was unable to answer. They told me I would not be able to view my credit report online.

Can someone,take out a mortgage using my social security number, even though I was 17 in April 2008? If so,what can I do, how will this affect my credit? Where do I go to find out additional information? Who would I report it to?

IF someone did that (and yes.. people do that, which is what id theft is all about), it will certainly mess up your credit.
Call again and ask to talk to a supervisor. You need to report this TO THEM and, probably in writing, with a copy of maybe your driver's license (that will show your age). State in the letter that you have reason to believe that there is fraud on your account, and why.
Legally, you have reason to get a copy of the information that will exactly identify the loan which is using that number. Since it apparently involves someone buying a house, that is big time fraud, not just against you, but against whoever they got the loan from.
Obviously.. if someone used your number for a home loan, you WOULD NOT have the info to answer any question about the loan. That's the whole point.
You may also want to be talking to your police dept if they have a fraud/ id theft unit.

You can put a fraud alert on your file. Look it up

http://www.consumer.gov/idtheft/con_step...

Also, call your State Attorneys General Office. The number is in the Blue Pages of your phone book. Look for the Consumer Protection Dept.