>>>Do you (or the server admin) install each SP?
>>
>>Good question. No we do not install the latest SPs and we paid for that recently. One of SQL servers 2000 started going down from time to time. We called MS support and they told us that SP4 will fix the problem and it did.
>>
>>> Can I download the latest SP on a flash drive and install it then? Would it be enough?
>>
>>I don't see why not.
>
>Thank you. My question was more of is SP4 is enough to install on RTM without all the others. I hope it will, I'll try to get it later today from a place with better Internet connection.

Yes, SQL SERVER SPs are cumulative.