What do the active Open statistics in the CMD mean?

I recently upgraded to Vista which I installed over Xp as I was having major problems with my pc and was told I probably had a rootkit,

It is still running slow and I rang my service provider and he went through all the usual stuff then told me how to check the active opens in the cmd which I did he said there should only be roughly 32 but there were 742,and I checked again today and it was up to 6000, what does it mean and is there anything I should do, he has got me panicking as I dont have a clue what it is and only have basic pc knowledge, please help, thanks in advance for any answers.