In what way is it "running slow". Is there a particular application that is running slow, or is it systemic? What applications are you running in terms of defensive software? Saying a computer is "slow" is like telling the doctor "I don't feel so good".

Also, did it run fine for a little while, and then it started to bog down again?

Picard's theory of a beat up HDD isn't crazy, but it is somewhat unlikely unless there has been physical damage to the drive that didn't kill it. Bad things happen to laptop drives all the time, becuase they get moved, which is kinda the point. Other possibiities are that you may have had some of your ram tank on you, or that it got rattled loose. OR, you restored your files and brought the virus right back in, or you have some really nasty spyware from a site you've visited (which is why I asked if it seemed ok for a little while). All of these things can make your system slow down, as can adding more defensive software, particularly if you go the silly route and have multiple apps with the same function.

I once saw a computer with THREE antiviruses (Nort, MacAfee and AVG) and FOUR firewalls (XP's waste of time, Norton, MacAfee and ZoneAlarm), and while it was well protected, they dogged it down to the point it could barely crawl. While that is the worst I've ever seen, it isn't an uncommon knee jerk reaction to being bitten to have a second AV or firewall put in. But it is like having a second airbag in your steering wheel- doesn't really do anything except make it harder to drive and use the first one.