Put the mbam installer on the desktop of the infected computer, right click on it, and rename it, anything you like, and see if it will install then. If that don't work, scour this section of the forum, and you will see many posts of people with the same problem with more detailed ways of getting mbam installed, updated, and ready to remove your malware.
Good luck.
My daughter has a virus(?) on her laptop which will not allow AVG to update. Access to the site is blocked, as well as access to most any site that has virus protection. I have tried downloading a number of virus scanners (mbam, ComboFix, Kaspersky). In many of the cases, I downloaded the programs on another computer, copied them to her laptop, but they will not install. In fact, nothing happens. Kapersky will install, but always stops because it thinks AVG is installed, but it isn't. The operating system is XP. Most other websites work, however if you try to do a search you get ads that pop up and the search will not work. I installed hijack this and posted the results on an anlyze site and removed a few items, svchost was in a wrong folder was the main problem on hijack this.
I greatly appreciate any help anyone can offer!!

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