USB is on in Bios I suppose (Actually that's legacy USB enabled, but it may help) Bios Setup is accessed via pressing usually DEL or F2 or F10, or whichever key it states when you first turn on the computer
Confirm USB is enabled
Then Save and Exit Bios Setup screen
Restart
Actually it may be Malware too
You should update your currently installed Antivirus, and run a full scan
You should also download and run >
Free Malwarebytes, and update it, and also run a full scan (note: removal of found Malwares is done right at the end when you press "Next")
Then Restart again (although Malwarebytes will likely do this for you)
Also you could download and run >
CCleaner
Run the cleaner, which will remove all useless temp files
And then click on the "Registry" button (still in CCleaner)
And "Scan" and then "Fix" all errors (note you need to do this about 3 times, to fix all registry errors)
Another Restart required, and test
If it still fails, then uninstall your Antivirus (or any other live protecting software (ie personal Firewall; or Spybots S&D that type of resident protection)
Then click on Start > Run >
SFC /Scannow (note: 1 space after SFC")
You may need your Windows Setup CD during the Scan/Fix, but
no files will be hurt running the scan, and your activation will remain intact)
Restart again, and then test again
Re-install your Antivirus (I recommend >
Free Avira Antivirus)
And update it again (note if you changed/updated to Avira, I'd recommend another full Antivirus scan)
Whatever the result, doing the above will help your system anyway
But please let me know, as there are still other options to try
By the way, are you running XP Service Pack 3 ?
)