OK, my issue is that I can't sign into AIM, MSN messenger or Yahoo Messenger, and I also cannot use any browser except for Firefox. I'm running Windows XP and this only happened recently.
Thanks for any help! Please download Malwarebytes Anti-Malware from Malwarebytes.org.
Alternate link: BleepingComputer.com.
(Note: if you already have the program installed, just follow the directions. No need to re-download or re-install!)

Double Click mbam-setup.exe to install the APPLICATION.

(Note: if you already have the program installed, open Malwarebytes from the Start Menu or Desktop shortcut, click the Update tab, and click Check for Updates, before doing the scan as INSTRUCTED below!)

• Make sure a checkmark is placed next to Update Malwarebytes' Anti-Malware and Launch Malwarebytes Anti-Malware, then click Finish.
  
• If an update is found, it will download and install the latest version.
• Once the program has loaded, select "Perform Full Scan", then click Scan.
  
• The scan may take some time to finish,so please be patient.
• When the scan is complete, click OK, then Show Results to view the results.
• Make sure that everything is checked, and click Remove Selected.
  
• When DISINFECTION is completed, a log will open in Notepad and you may be prompted to Restart. If you are prompted to restart, please allow it to restart your computer. Failure to do this, will cause the infection to still be active on the computer.
• Please save the log to a location you will remember.
• The log is automatically saved by MBAM and can be viewed by clicking the Logs tab in MBAM.
• The log can also be found at C:\Documents and Settings\Username\Application Data\Malwarebytes\Malwarebytes' Anti-Malware\Logs\log-date.txt or at C:\Program Files\Malwarebytes' Anti-Malware\Logs\log-date.txt
  
• Copy and paste the entire report in your next reply.