Can't get past Welcome

Children played on the Dell Dimension the other day and it locked up. Computer was shutdown and restarted. The XP Welcome screen comes up with the different user on the right side of the screen. I am able to highlight each user with the mouse, but the user's setting will not load. By pressing various keys on the keyboard, I managed to get to the Desktop, but once again the computer is not responding to the mouse. I have checked the batteries on the wireless mouse, the keyboard is also wireless. There are some applications that are running that pop up such as my Antivirus program which tell me that something is working. Need some ideas for areas to check or some articles to read.
Thanks

I'm currently operating on a computer at work.

 

A quick 'n' dirty workaround might be simply to install a PS/2 mouse temporarily, just to see if you can use it to work within Windows. If you DO get into Windows, do this:

Start > Run

Type "CMD" in the box (no quotes), and press Enter, or click the OK button...

The Windows Command Prompt will open (looks just like an old black DOS window)...

At the prompt, type this:

CHKDSK /F

That is the letters CHKDSK, followed by a SPACE, followed by a SLASH, then the letter F

CheckDisk will tell you that it can't lock the file system, and ask if you want it to run at the next reboot. Type a Y, then press Enter.

Next, type EXIT to close the Command Prompt, then reboot.

When the system restarts, CheckDisk will run and try to repair the file system...

This forum will go offline at 2 PM Eastern time, to work on the servers:

http://forums.techguy.org/site-comments-suggestions/645880-scheduled-downtime-sat-nov-3-a.html

with no way of knowing when it will be back online, so in case you don't have time to reply before they shut the servers down, best of luck to you with this... I'll check for an update from you when the TSG forums go back online... keep us posted, and let us know if swapping the mouse doesn't work...