I would do the following things in the order listed: 1.
Run a full scan with your updated anti-virus suite. Since no anti-malware product is 100% effective 100% of the time, I would run a couple of additional on-demand scanners just to double check my computer. These free products are recommended: Malwarebytes ESET Online Scanner SuperAntispyware HitmanPro 2.
If the malware scans come back clean I would next check for damaged or corrupt system files. Run a system file checker scan from an elevated command prompt (option two.) If problems are found, run the scan 3 times and reboot the computer after each scan. SFC /SCANNOW Command - System File Checker 3.
Go to the Microsoft Download Center and get the Windows 7 64-bit System Update Readiness Tool for your version of Windows 7. Follow the instructions to run it. System Update Readiness Tool fixes Windows Update errors in Windows 8, Windows 7, Windows Vista, Windows Server 2008 R2, and Windows Server 2008 4.
Before attempting to install SP1 I would first try to manually
install the other Windows Updates. Do not do an automatic install because if one of the updates hoses your computer you won't know which one it was. Select "Never check for updates (not recommended)" in Step 3. Windows Update Settings - Change 5.
When manually installing updates start with the Critical, then Important, and finally Optional. Select maybe two at a time and keep track of the KB numbers. After installing, reboot the computer and make sure things are working the way they should. If they are, select the next group of two, install and reboot. But if your computer doesn't work properly, you'll know exactly which two updates need to be uninstalled. Then try installing just one at a time and reboot after each one. They'll either install correctly or you can put the problem update aside and move on to the next group of two. Continue until all updates have been installed. This is a much slower process but usually results in a cleaner install of updates. 6.
Once you've installed the updates try installing SP1