Solved WIN 7 suddenly very slow

Make sure to use this tool to uninstall Norton completely: http://www.majorgeeks.com/files/details/norton_removal_tool.html

Also reverse all changes you made in "msconfig ".

 

Good news

Make sure you install some AV program.

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Your computer is clean

1. This step will remove all cleaning tools we used, it'll reset restore points (so you won't get reinfected by accidentally using some older restore point) and it'll make some other minor adjustments...
This is a very crucial step so make sure you don't skip it.
Download DelFix by Xplode to your desktop. Delfix will delete all the used tools and logfiles.

Double-click Delfix.exe to start the tool.
Make sure the following items are checked:

• Activate UAC (optional; some users prefer to keep it off)
• Remove disinfection tools
• Create registry backup
• Purge System Restore
• Reset system settings

Now click "Run" and wait patiently.
Once finished a logfile will be created. You don't have to attach it to your next reply.

2. Make sure Windows Updates are current.

3. If any trojans, rootkits or bootkits were listed among your infection(s), make sure, you change all of your on-line important passwords (bank account(s), secured web sites, etc.) immediately!

4. Check if your browser plugins are up to date.
Firefox - https://www.mozilla.org/en-US/plugincheck/
other browsers: https://browsercheck.qualys.com/ (click on "Scan without installing plugin" and then on "Scan now ")

5. Download, and install WOT (Web OF Trust): http://www.mywot.com/. It'll warn you (in most cases) about dangerous web sites.

6. Run Malwarebytes "Quick scan" once in a while to assure safety of your computer.

7. Run Temporary File Cleaner (TFC), AdwCleaner and Junkware Removal Tool (JRT) weekly (you need to redownload these tools since they were removed by DelFix).

8. Download and install Secunia Personal Software Inspector (PSI): http://secunia.com/vulnerability_scanning/personal/. The Secunia PSI is a FREE security tool designed to detect vulnerable and out-dated programs and plug-ins which expose your PC to attacks. Run it weekly.

9. (optional) If you want to keep all your programs up to date, download and install FileHippo Update Checker.
The Update Checker will scan your computer for installed software, check the versions and then send this information to FileHippo.com to see if there are any newer releases.

10. When installing\updating ANY program, make sure you always select "Custom " installation, so you can UN-check any possible "drive-by-install" (foistware), like toolbars etc., which may try to install along with the legitimate program. Do NOT click "Next" button without looking at any given page.

11. Read:
How did I get infected?, With steps so it does not happen again!: http://www.bleepingcomputer.com/forums/topic2520.html
Simple and easy ways to keep your computer safe and secure on the Internet: http://www.bleepingcomputer.com/tutorials/keep-your-computer-safe-online/
About those Toolbars and Add-ons - Potentially Unwanted Programs (PUPs) which change your browser settings: http://www.bleepingcomputer.com/for...curity-questions-best-practices/#entry3187642

 

Way to go!!
Good luck and stay safe