I have not run into the kinds of issues you have as I have always done a clean install (no in-place upgrades). But if I had, I would just stop, re-access and do a clean install. In the long run it saves time and you can be assured it is running correctly as there is the potential for things going wrong otherwise. Follow the upgrade guide posted, install an anti-virus program, run Windows Update, defrag.
Prior to that, disconnect any printers, USB devices, etc. Go to Dell's site, enter your service tag and get the drivers you need. Have the latest drivers already downloaded and on a flash drive or on one of your partitions. After the OS loads
, install your chipset (motherboard) drivers first.
Check Device Manager and then back it up! Make a system image prior to installing your applications so if something goes wrong you just load the image instead of starting from scratch. After you get everything else installed and running correctly, run Windows clean up, defrag and back up the whole thing.
If you are not certain how a driver or application will behave, create a System Restore point prior to loading it. There is a tutorial here:
http://www.sevenforums.com/tutorials/700-system-restore.html?filter[2]=Backup%20Restore
Before starting, READ the tutorial on a clean install previously posted (no Vista involved), read how to create System Restore points if needed and have all drivers and applications at hand. In other words, have a plan and follow it.
Choose Option 1 from here:
http://www.sevenforums.com/tutorials/31402-clean-install-upgrade-windows-7-version.html?filter Then go from here:
http://www.sevenforums.com/tutorials/1649-clean-install-windows-7-a.html
Free back-up software:
http://www.todo-backup.com/ or Windows 7 back-up:
http://www.sevenforums.com/tutorials/663-backup-complete-computer-create-image-backup.html?filter[2]=Backup%20Restore
http://www.sevenforums.com/tutorials/700-system-restore.html?filter[2]=Backup%20Restore
One last thing. When you run Windows Update, it will want to download the latest version of Internet Explorer. You can either just run Express and it will download or choose Custom and run Windows Update again later to grab it.