Not really but some things you could try to start off with.
Start in safe mode. (Press F8 during startup and select safe mode from the menu) Does the same thing happen? If it starts ok in safe mode, check your startup folder (right click start button, open, double click programs, double click startup). Move things out of there one at a time to see which if any is causing the problem.
Secondly while in start mode, use msconfig (start, run, enter msconfig, ok, startup tab) to see what else is running at start up. Again untick them one at a time and see if anything here is causing it.
Thirdly while in safe mode, run your virus checker and adaware and spybot if you have them.
Is your virus checker up-to-date? If not make it so and then run it.
Another thing you can do at the welcome screen is press ctl-alt-dlet twice. This brings up the old W2000 logon and you should be able to logon as Administrator without a password. (This assumes you're running XP home and didn't explicitly set an administrator password). If you can logon as Administrator you can delete the id you are having trouble with (start, control panel, user accounts, select user id and delete, remember to accept the option to save files) and then create another one.
If none of this helps, sorry, you may have to re-install, unless someone else has an idea.