having problem installing avast on xp prp 64 bit

I have downloaded the free version of avast. When I run Setup the progress bar appears with the file folders transfering then installation just stops> any suggestions??

Do you have any antivirus program installed on the computer ?

If so you need to uninstall that program before installing avast.
After you have uninstalled it it is recomended to run a removal tool so all leftovers are gone
You can find the tool here http://uninstallers.blogspot.com/ run it reboot and then try installing avast

No AV apps installed. just got rid of the fraud Spy Doctor tho.

Then i recomend trying this, you may have something that is blocking the install

Check your computer for Malware with

Malwarebytes Antimalware http://filehippo.com/download_malwarebytes_anti_malware/
after install click UPDATE and run quick scan, click on REMOVE SELECTED to quarantine anything found

SUPERAntiSpyware http://filehippo.com/download_superantispyware/
Are cookies really spyware and are they dangerous?
http://www.superantispyware.com/supportfaqdisplay.html?faq=26

If anything is found come back and post the scan logs here