What is the brand and model of your windows xp computer?
What is not working on your computer?
Can you login your computer?
Do you have the windows xp / recovery disk?
Let's try the following:
Please try this: turn off your computer. Then turn it on, and right after the black screen with white text or the computer company logo disappears, press & release key F8 repeatedly until a menu appears, then you select Safe Mode with Networking (note: if there is no menu, then try the same steps again, but this time, press key F8 a bit earlier). Then login and click Start->all programs->accessories->system tools->system restore and restore the computer to any date before this issue has occurred.
If that does not work, please go to Safe Mode with Networking again, then click below and click on download now, to download and install the anti-malware software. Then scan your computer: http://download.cnet.com/Malwarebytes-Anti-Malware/3000-8022_4-10804572.html
Please let me know how it goes.
Did the scan find anything?
So now if you open any program, what happens?
Can you go to Start->Control Panel->User Accounts and create a new account?
it's all right
Then restart the computer and login the new account and see.
What happens when going to Start->Control Panel->User Accounts->Manage another account?
If you can.
Ctrl and F11 when you see the dell logo appears
1 Turn on the computer.
2 When the Dell splash screen appears during the computer startup process, press and hold <Ctrl> and then press <F11>. Then, release both keys at the same time.3 In the Dell PC Restore by Symantec window, click Restore. Alternatively, press <Tab> to highlight Restore, and then press <Enter>.
If that does not work, then you need the Windows XP / Recovery disk, which you can get from Dell website:http://support.dell.com/support/topics/global.aspx/support/dellcare/en/backupcd_form
Please let me know if you have any question later. Thank you.