DEF - are you sure you don't mean DEP (Data Execution Prevention)? Vista up to date with Windows Updates? Does DEP prevent the installer itself running, or the program when it's actually been installed?
Huawei P10 review
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New iPad, iPhone SE & Red iPhone 7 on sale now
Synology invites you to visit them at Insomnia on 26th – 29th August. Book your tickets now and visit Synology.