Virus personal security download keeps blocking me from doing anything without purchasing the program

Personal Security is very wisely denominated rogue antispyware. Most users figure out what sort of software they have and ask how to remove Personal Antivirus
To remove Personal Security spyware you must block Personal Security sites, stop and delete processes, unregister DLL files, search and delete all other Personal Security files and registry utility. Other software removal method is to remove Personal Security by using "Add or Remove Programs" service. However there may be hidden Personal Security files, running processes and registries in your computer, so Personal Security may recreate all other files after reboot.

I assume you're running some flavor of Windows?
Go to www.malwarebytes.org, download the free version of that software, run an update, and perform a scan.
If that doesn't work, the best solution that I've come across online is at this site:
http://www.bleepingcomputer.com/virus-removal/remove-personal-security
the solution is about halfway down, and the answer is pretty descriptive - it should do the trick.
last suggestion: try to reboot and boot in safe mode (press F8 a couple of times as you see the initial splash screen right after you turn the computer on), select safe mode with networking, then go to the above site, run that rkill.com thing then run MBAM.
That should do the trick!