Win 8 Upgrade Issues and Reinstalling Windows 7 help

Hello,

I bought windows 8 and tried to install it last night over my windows 7 computer, however the upgrade keeps failing for some reason (it does not give me a code or error message-all it does it try to install-reboot and it is 100% installed-and then it goes to a screen where I need to pick what OS to start with - Win 8/Windows Config (or something) / Win 7 ) - each time I pick Win 8 or Win config, it encounters an error and reboots. The only way for me to get out is to pick windows 7 and it brings me back to win 7 saying it is right where I left off before the install and "We're sorry we had a problem installing windows 8".

Anyhow, I ran the upgrade checker and only had a couple issues with software programs- A game (which I installed a patch for but showed up again anyhow), and intel disk manager software-(I updated and fixed) and one other item that I cant remember, but it wasnt critical and was willing to let it go. My computer has crashed several times in the past two years where it would not boot, and the only way I was able to get it functioning again was by using Comodo Time Machine which I have installed. I'm not sure if this causes any upgrade issues but it has saved me multiple times. I probably should do a clean install of Win 7 because I do believe it is a bit corrupted, but still functioning. My computer has more than enough to handle Win 8 (8 GB Ram, i7 processor, etc) so I know that isnt the issue.

I do have a feeling that my Win 7 is probably operating at less than 100% (but still functions OK), and thought about just biting the bullet and doing a clean custom install. I bought my computer in 2009 which came from Dell (XPS 9000 or something) with Vista and received an upgrade disk for Win 7 a month later. Finally, my questions:

1-Anyone have any ideas as to why Win 8 wont install? Is it because my Win 7 installation is likely somehow corrupted?
2-I assume the best course of action here is to clean reinstall Win 7, if I want to be able to use Win 8 on my computer-I saw the tutorial that you can reinstall from an upgrade disk-but will it work from a DELL Win 7 upgrade disk?
3-Does anyone have any other suggestions? I went through the CFD scannnow as well and it says it corrects errors but if I run it again it says the same thing.

thanks for the help.
Dan

Forgot to mention that the upgrade I am using is the $40 one I purchased online in January- I am trying to install from the email I was sent from microsoft-I click on the icon it made on my desktop and install from there-not from a disc or flash drive. Dont know if this matters.

I would stick with Win7 and follow these same steps to get a perfect Clean Reinstall - Factory OEM Windows 7.

When you boot the installer, delete all other partitions using Drive Options in Step 7 of Clean Install Windows 7.

Then if you want, save a space at the right end of the HD to Clean Install - Windows 8 in a Dual Boot to compare it later. You'll have 30 days to decide before it must be activated. If you don't want it just delete it in Disk Mgmt and extend the Win7 partition. If you want to get rid of Win7 you'll need to mark 8 Active and run Automatic Repair - Run in Windows 8 then you can Partition Recover Space Used by an Older OS