HELP!! Software will not install on 7

Sort of a noob here, so go easy on me.

I performed a clean install of Windows 7 last night on a brand new, Quad core PC that I built from scratch. It has a 500gb HD and 4gb Ram.

Note- I had two hard drives so in the process I installed 32 bit on one and then I got curious and installed 64 on the other- SAME errors on both.

So I had installation disks from work, and I purchased the key from a friend. I installed 7, and installation went just fine. The problem was after that. The ONLY software that I can get to install is Microsoft Project 2007. NO other software will install. I have tried WordPerfect X4, I have tried Quickbooks(and yes I tried it in XP mode). I tried installing the software for my Wireless USB device, and then I tried installing software for my printer. NOTHING!!!! I get different errors everytime too- For example: "SetupARP.exe has stopped working," or "802.11 device did not install properly." Different every time.

Does anyone have any idea?

I thought of that too, but I guarantee that they are all compatible. I have the exact same programs running on a 32-bit machine at work. Well, all but the 802.11 device. So compatibility is not the issue here.

Thanks though.

I understand that Kid. I am not online, so there was no risk of authentication. I removed one hard drive and put the other one in to try it. But I do understand that as soon as the key authenticates, then I will only be able to have it on one machine.

Thanks for the help Rich. I hadn't thought of the cleanboot. I am at work, but I will give it a try when I get home.

Thanks again.

No worries Kid! I know you are trying to help.

Thanks!

Update- So I unlocked the Administrator account, but that didn't seem to work either. So then I went into the computer performance options and changed the Data Execution Prevention setting- (Right click "My Computer", select "Properties", "Advanced Settings", "Settings" under the Performance tab, and then clicked the "Data Execution Prevention" tab. I changed the setting to "Turn on DEP for all programs and services except those I select." And then SHAM-WOW! It worked. I have installed everything I needed so far.

SO my question is whether or not I did something bad :) ! Or maybe it is just coincidence that it all started working after I changed that setting..?

Anyways, if anyone knows much about this setting, please let me know. Thanks.