how can i fix my pc?

One with service pack 1 and one with service pack 2 mean that they are NOT the same.

As Windows 7 don't have a service pack 2, it means that you are probably still using Windows XP.
You MUST update to service pack 3 as soon as possible, then apply ALL available updates.
You don't need to go to the Microsoft site to get them. Use the Windows Update application that you should find in the start menu.
If you have Vista, install the service pack 2 on the one still using service pack 1.
Install ALL availabla patches and updates from Microsoft via the automatic updates service.

Another option, wether you are running Windows XP or Vista, is to upgrade to Windows 7.
Most computers capable of running Windows XP and ALL those running Windows Vista can run Windows 7 without any problem.

Much more robust and safer than both XP and Vista, and faster than Vista.

Upgrading to Windows 8.1 is also a viable option, but you'll be hit by some huge change regarding the interface.

No mather whitch option you choose, be sure to turn ON the automatic updates and set it to download and apply the periodic updates as they become available.

Finaly, especialy if you are short on cash and want to stay fully legitimate, you can switch to Linux. There are a LOT of distributions to choose from. Less superficial/user interface changes than going to Windows 8/ 8.1...

Linux also have an automatic updates mechanism that is ON by default and should be left ON.

Here a great place to visit if you are interested to switch to Linux:
http://distrowatch.com/
It's a portail to the various Linux distributions and flavours.

Electro
October 2014

You do not say what's wrong with your PC - either of them

Much will depend on the Operating System (OS)
Windows XP has had 3 service packs released
Vista 2 packs
W7 1 pack
W8 W8.1 Update


http://windows.microsoft.com/en-GB/windows/service-packs-download#sptabs=win81

Service Pack and Update Center

Get the latest service pack or update for your version of Windows
A service pack (SP) is a Windows update, often combining previously released updates, that helps make Windows more reliable. Service packs, which are provided free of charge on this page, can include security and performance improvements and support for new types of hardware. Make sure you install the latest service pack to help keep Windows up to date. Service packs take about 30 minutes to install, and you'll need to restart your computer about halfway through the installation.

W Gates
October 2014