Why is my computer having problems after I got rid of the malware?

The malware "XP Antivirus 2010" had infected my computer. After doing many scans to find and delete this, I find the malware gone, but my computer is acting funny. Everytime I open a program it asks me to tell it what program to use?!? I am being asked what program use to open a program?!? I cannot do a System Restore because previously I had it turned off.|||one of the side effects of removing bugs, they get attached to system files, and when they go so sometimes do parts of system. might be someone here to help better, but with a windows disk it does have a repair feature in it. that pop up yer getting might give you options.|||Reinstal the system with the CDs/DVDs you should have got with the laptop.|||A Windows file got damaged. Do a Windows repair - http://webdingers.com/wordpress/2010/03/鈥?/a>|||download microsoft security essentials from microsoft.com


or do a system recovery