Microsoft has released SP1 for Windows 7 month or so back, but many few of the users had downloaded it via direct link and rest had leaved the job on Windows Update.
Many times windows update wont be able to download updates due to lows speed or you had made setting which wont allows it to download.
There are some applications out there which ask you to have SP1 installed in Windows 7 and if you are confused whether you had installed SP1 or not then here is quick way to find it.
All you need to do press Windows Key + Pause/Break key and System Information dialog box comes, Just look at Windows Edition section, first you will find the edition of Windows you are using like Windows 7 Ultimate and then if you had installed SP1 then it will show Service Pack 1 otherwise it will be blank.
See the two screenshots below, first one is without Service pack and second one with SP :-
There is another simple way and its via Windows About dialog box, for it type winver in run command and you will see a box like below :-
If you find that Service pack is not installed in your computer then you can install it via Windows Update.