Using activators to activate the paid softwares is not at all recommended, there are many activators available on the internet but you should use them.
Most of the activators are viruses and they are not safe at all, you can be a victim of internet phishing. I would say that you should buy the original license key to use such important softwares like Microsoft Office 2010.
And if you really don’t want to buy it, then you can use some free office softwares.