Hi! My laptop is becoming increasingly slow as if there is a virus. Firefox keeps asking me whether I can to stop a script, GOOGLE chrom says about a PLUGIN that has crashed but in general sometimes I think it has frozen all together.

I just for that on a screen a while ago

resource:///components/nsSessionStore.js:402

Any idea as to what it is and above all what I can do for my computer to run properly?

thanks,
 Hello and welcome to GeekPolice.Net My name is Dave. I will be helping you out with your particular problem on your computer. 

1. I will be working on your Malware issues. This may or may not solve other issues you have with your machine.
2. The fixes are specific to your problem and should only be used for this issue on this machine.
3. If you don't know or understand something, please don't hesitate to ask.
4. Please DO NOT run any other tools or scans while I am helping you.
5. It is important that you reply to this thread. Do not start a new topic.
6. Your security programs may give warnings for some of the tools I will ask you to use. Be assured, any links I give are safe.
7. Absence of symptoms does not mean that everything is clear.

If you can't access the internet with your infected computer you will have to download and TRANSFER any programs to the computer you're using now and transfer them to the infected computer with a CD-RW or a USB storage device. I prefer a CD because a storage device can get infected. If you use a storage device hold the shift key down while inserting the USB storage device for about 10 secs. You will also have to transfer the logs you receive back to the good computer using the same method until we can get the computer back on-line.
*****************************************************************
SUPERAntiSpyware

If you already have SUPERAntiSpyware be sure to check for updates before scanning!

Download SuperAntispyware Free Edition (SAS)
* Double-click the icon on your desktop to run the installer.
* When asked to Update the program definitions, click Yes
* If you encounter any problems while downloading the updates, manually download and unzip them from here
* Next click the Preferences button.

•Under Start-Up Options uncheck Start SUPERAntiSpyware when Windows starts
* Click the Scanning Control tab.
* Under Scanner Options make sure only the following are checked:

•Close browsers before scanning
•Scan for tracking cookies
•Terminate memory threats before quarantining
•Please leave the others unchecked

•Click the Close button to leave the control center screen.

* On the main screen click Scan your computer
* On the left check the box for the drive you are scanning.
* On the right choose Perform Complete Scan
* Click Next to start the scan. Please be patient while it scans your computer.
* After the scan is complete a summary box will appear. Click OK
* Make sure everything in the white box has a check next to it, then click Next
* It will quarantine what it found and if it asks if you want to reboot, click Yes

•To retrieve the removal information please do the following:
•After reboot, double-click the SUPERAntiSpyware icon on your desktop.
•Click Preferences. Click the Statistics/Logs tab.

•Under Scanner Logs, double-click SUPERAntiSpyware Scan Log.

•It will open in your default text editor (preferably Notepad).
•Save the notepad file to your desktop by clicking (in notepad) File > Save As...

* Save the log somewhere you can easily find it. (normally the desktop)
* Click close and close again to exit the program.
*Copy and Paste the log in your post.
*********************************************
Please download Malwarebytes Anti-Malware from here.
Double Click mbam-setup.exe to install the application.

• Make sure a checkmark is placed next to Update Malwarebytes' Anti-Malware and LAUNCH Malwarebytes Anti-Malware, then click Finish.
  
• If an update is found, it will download and install the latest version.
• Once the program has loaded, select "Perform Full Scan", then click Scan.
  
• The scan may take some time to finish,so please be patient.
• When the scan is complete, click OK, then Show Results to view the results.
• Make sure that everything is checked, and click Remove Selected.
  
• When disinfection is completed, a log will open in Notepad and you may be prompted to Restart. (See Extra Note)
• Please save the log to a location you will remember.
• The log is automatically saved by MBAM and can be viewed by clicking the Logs tab in MBAM.
• Copy and paste the entire report in your next reply.

• Close any open windows and double click ComboFix.exe to run it.
  
  You will see the following image: