User+Name+you+can+have+a+space+in+yours

User Name you can have a space in yours

The answer is technically yes, XP will allow you to use spaces within the user name. However, it is not advisable to do it. Some application programs are not coded to handle that and you might get some weird behaviour. You'll also have problems with command line tools that don't play well with spaces.

Having said all that you could do something similar.

First make the user account name all one word. Then go to the User Accounts home page from Control Panel and at the bottom, click the name of your account. Click Change My Name. When you set up the account, XP makes the name displayed on the Welcome screen and Start menu the same as the account name, but you can change the display name here, without changing the account name. So change it to the full name with the space and you will get what you want on the Welcome screen without causing any problems for programs.  