Can't install downloaded software! Error.

[maximus2688]

not long ago, i built my computer and it runs great. but, there's one problem. whenever i download any software from the internet, i begin to install it and... BOOM... messages similar to this appear: "the contents of this file cannot be unpacked. the executable you are attempting to run has been corrupted. please obtain another copy of the file, verify its integrity, and try again." - ERROR: -5001 (but it doesnt always show the error #) - it's not always the same exact, but the meaning is the same. so, i cant install anything that's d/loaded. i have to go to my other pc to d/load, and transfer data to my new pc.
i did some research on this and found out that it may be my network settings or the motherboard drivers of some sort (network - i believe) that are causing this.
i would really appreciate if someone helped me solve this problem. it's pretty time consuming to download programs on one pc and transfer them to another
thanks a lot in advance!

[glc]

Think it just might have something to do with the virus you had that was rebooting your computer? Time to run some more scans, spend some time reading the sticky threads and other stuff in our Security forum.