First of all, you don't unsubscribe from ads. If you do try to unsubscribe, they will know your E-mail is real and works.
Second of all, your PC is probably compromised beyond recognition:
Virus scannersAVG Free-- Anti virus scanner
Trend Micro Housecall-- Online anti virus scanner.
Anti spy/malwareMicrosoft Antispyware-- Anti spyware scanner. Windows XP Home and Professional only.
Spybot Search & Destroy-- Anti spyware scanner
Adaware SE Personal-- Anti spyware scanner
FirewallsUse both a hardware and software firewall.
Be advised as dual software firewalls may cause problemsZoneAlarm Free-- Free firewall - more user friendly
Sygate Personal-- Free firewall - more configuration options
Removal toolsThe following files are not substitutes for the ones described above.
They are either diagnostic tools or removal tools for malware of a certain kindHijackThis-- Manual malware remover. Post the HijackThis log generated
only if requested!
McAfee Stinger-- Virus removal tool.
No substitute for a fully functional virus scanner!CWshredder-- CoolWebSearch removal tool. Widely known and persistant Hijacker.