Unable to download anything IE8 & Vista

[tangoman]

I appologise for lack of knowlege & experience but I  have been unable to save any download since my AVAST trial period is expired about a month ago.
I have disabled my antivirus software  again it appears to download but  when I try to Run the box closes & nothing happens.
I have tried system restores but they are all to recent so do not fix the problem.
I have previously registered AVAST and have inserted the activation key but when I try to run I get  AAVM subsystem detected a RPC error.

I had stopped AVAST on vista control panel but I then get program can not activate resident part (standard shield provider not present)
I had previously tried to uninstall AVAST but this had failed.

I now think I have a virus as the system is crawling but I am unable to download any malware detection software  as it appears to download the file but when I try to run nothing happens.
 

Can anyone suggest any simple ideas to remove virus and get downloads working ?

[.: L' arc :.]

Step 1: Windows Disk Cleanup Utility ============

1   Press Windows Key + R
2   Type in: cleanmgr
3   Put a check beside: Temporary Internet Files and Temporary Files. Optionally, you may check other options too
4   Click OK

Step 2: Malwarebytes Antimalware (MBAM) ============

1   Download Malwarebyes' Antimalware here
2   Proceed to installing MBAM after downloading
3   On the last dialog box, do not forget to leave Update Malwarebytes' Antimalware and Run Malwarebytes' Antimalware checked
4   Malwabytes' Antimalware GUI would appear, from there select Perform Quick Scan and click Scan
5   When scan is completed, click Show Results
6   Click Remove Selected and then, a notepad file will appear.
7   On the notepad window, click File > Save As and save it on your desktop. You may now close MBAM.

Step 3: Hijack This (HJT) ============

1   Download Trend Micro Hijack This here
2   Install HJT in C:\Program Files\Trend Micro\HijackThis (the location is already displayed by default). Click Install
3   HJT Window will appear. Click Do a system scan and save a logfile. A notepad file will pop-up once the scan is completed
5   Click on the Notepad window and click File > Save As and save the file on your desktop
6   Go back here on your topic and start a reply. On the Reply window, click Additional Options
7   Attach the two .txt files that we created and saved on your desktop (click more attachments to have more slots for attaching files)
        NOTE: Do not have HJT fix anything yet.

[tangoman]

THanks L'Arc I have completed step 1, but because I can not download anything step 2 does not run.

I can either Run or save mbam-setup.exe but either way they appear to work (100 % complete) but do not do anything.

Any suggestions?

[Pondus]

If you try following this removal guide.( i now it is not the issue you have)
It is the the step 2 and 3 in the guide to get Malwarebytes up and running i am after, so just follow the hole guide and see if it works

http://www.bleepingcomputer.com/virus-removal/remove-security-tool

[tangoman]

I was unable to follow steps 2 & 3 as I could dowmload the required files but I did manage to save the rkill & mban-setup applications on a memory stick via a desktop that does not have this download problem.
I then executed these on the affected Vista laptop & installed both applications and after running the Malwarebytes product I managed to remove 1 trojan but there were not any rogue.securityTool errors.

After removing the Trojan I still can not download/save from IE8 onto my vista system any ideas on how can get this useful feature back?.

Thanks
Dave