A re-directed link could be a sign of malware, but it's also a technique used by spammers 'spoofing' or faking a web address. That 'Canadian' drug company is actually hosted in Russia, by the way!
Doing a System Restore is useless if malware was installed - usually malware gets deep into your system. Change the password on your e-mail account to at least a random 12+ character one.
In case of possible malware, read the below advice.
Don't use your computer until you have done scans several times in Safe Mode with Networking, which catches and cleans far more than normal boot-up mode. (Hold down the F8 key when the computer screen first lights up, until you hear a beep or see a new dark screen. Then use the arrow keys and Enter to get to Safe Mode with Networking) Be sure you are logged in as an Administrator. Start by scanning with your current anti-virus program, then download and install the following anti-malware cleaners. Update them. Re-boot into Safe Mode for each scan. If it is a bad infection, use a clean computer to download and burn to a CD/DVD. With the CD/DVD in the drive you can execute the anti-malware programs from there. If you use a flash or thumb drive, it could also get infected, but it can be used for most scans safely.
When the scan runs clean, update all tools used before (except Housecall) and run again with the updated files. First run your regular anti-virus program, then you should scan with several different anti-malware programs, since they catch different things, but only one should run constantly.
http://www.malwarebytes.org/mbam.php (free version, update before running)
http://www.superantispyware.com/ (also free, update before running)
http://housecall.trendmicro.com/ (an online scanner, always up-to-date)
Once clean, remove all System Restore points (Start > Programs > Accessories > System Tools > System Restore > delete ... small, in left panel) for XP or (Start > Right click Computer > Properties > System Protection), select any hard drives with protection on, press Configure..., and turn off system protection. Then re-enable it (deletes all restore points). before re-booting for Windows 7. This prevents any malware from re-installing itself. Of course, once you re-boot in Normal Mode, re-set a new System Restore point right away. If you have detected malware on your computer, change all of your passwords after cleaning up the infection.
These are reputable FREE sources. You should scan with several different anti-malware programs, since they catch different things, but only one should run constantly.
http://www.malwarebytes.org/mbam.php (free version, update before running)
http://housecall.trendmicro.com/ (an online scanner, always up-to-date)
http://www.superantispyware.com/ (also free, update before running)