I just looked at "slow computer" and found the only solution to be toolbars, which is almost last on the list for us when it comes to a proper diagnosis.
I think if you added more options, there would be more value to someone callling in. Things such as...
1.) test your internet speed
2.) download our virus checker yourself and if you are infected, we can help
3.) has your computer been tuned up lately? If not...
4.) Is just your internet slow, here is how to reset your internet.
I think you know where I am going with this. These are easy things people can do anyway via the internet searches, do you really want to make money on telling people all they had to do was flush their internet or offer a full tune up and give them value?