since installing windows 8 my computer is very slow to boot up?

Hi Jonniboy,

Thank you for posting your query in Microsoft Community forums.

I understand that your computer is slow after installing Windows 8.

Let us follow the troubleshooting steps listed below and try to fix this issue, but before we proceed let me know the follow information.

1)      What is the make and model of the computer?

2)      Is Windows 8 upgraded or clean installed?

3)      Is your computer shut downs faster?

4)      Are you using Microsoft account or local account to log in?

Now let us follow the methods step by step and check if the issue is fixed.

Method 1: Perform “System maintenance troubleshooter”

a)      Press Windows key + X, Select Control Panel.

b)      In the search box, type troubleshooter, and then click Troubleshooting.

c)      Under System and Security,

d)      Now click System maintenance.

e)      And follow the steps.

Method 2: Let us perform a safe and clean boot and check if the issue persists.

Step 1: Perform Safe Mode

Boot the computer in Safe mode using the Windows 8 DVD. Follow these steps to start the computer in safe mode.

Click the link and follow the steps “Windows Startup Settings (including safe mode)”

http://windows.microsoft.com/en-US/windows-8/windows-startup-settings-including-safe-mode

Check if you face the same issue in safe mode. If the issue doesn’t persists in safe mode, the place the computer in clean boot and check.

Step 2: Perform Clean Boot.

To help troubleshoot error messages and other issues, you can start Windows 8 by using a minimal set of drivers and startup programs. This kind of startup is known as a "clean boot." A clean boot helps eliminate software conflicts.

http://support.microsoft.com/kb/929135

Important: Reset the computer to start as usual.

Note: After you have finished troubleshooting, follow these steps to boot to normal startup.

a)      Press the ‘Windows + R’ key on the keyboard.

b)      In the ‘Run’ windows type ’MSCONFIG’ and click ‘Ok’.

c)      On the ‘General’ tab, click the ‘Normal Startup’ option, and then click ‘OK’.

d)      When you are prompted to restart the computer, click ‘Restart’.

Ways to improve your PC's performance

http://windows.microsoft.com/en-IN/windows/performance-maintenance-help#performance-maintenance-help=windows-8&v2h=win7tab1&v3h=winvistatab1

Hope this resolves the issue. Do get back to us if the issue still persists or if you have any other Windows related issues, We will be glad to assist you.