1) Look in Add/Remove Programs for any programs you don't recognize, then Google those programs as ("insert Name of Program" + spyware) and see what comes back. Uninstall any programs that you determine are spyware.
2) Download Spybot S&D and AdAware and run both programs. Delete any spyware found. Reboot computer and start in Safe Mode. Re-run Spybot and AdAware, deleting any spyware found.
3) If spyware symptoms persist, download and install the free trial of Webroot Spy Sweeper (which seems to have a more comprehensive database to draw upon than Spybot or Adaware). Run Spy Sweeper, make a note of any spyware found in case Step 4 is needed, and delete all spyware found. Reboot in Safe Mode, and repeat the procedure.
4a) Registry editing - This is where you have to go a bit 'freestyle'. Backup the registry and/or create a system restore point. Reboot in safe mode. Using regedit or any other registry editing utility, search the registry for the names of any spyware you recorded from Step 3. Delete values and/or keys as needed.
4b) If after all this Spy Sweeper still detects spyware trying to reload, again Google the name of the spyware (see Step 1). This time, look for a reference to deleting a registry key or value that might not be as obvious as the name of the spyware. If you find such a reference, repeat Step 4a and delete the specified key(s) and/or value(s).