Sciz

Ok, well first, never delete a .dll file unless it is found by a virus scanner and listed as a virus. .dll files are system files that if deleted, can truly screw up your comp, as you can tell. Second, you said that you tried an upgrade but never listed which you upgraded to. So which Operating system are you currently running now? Third, that blue screen you saw is considered the BSOD or Blue Screen of Death. It seems scary at first but usually it's really not that big of a deal unless you consistently get it. And lastly, if you have the original install disc try to boot from the CD Rom.

If you're not setup to do this what you need to do is when the computer restarts and you see a screen that should say something along the lines of press DEL to enter setup or TAB to post the bios information. You will want to press the DEL key which on a standard keyboard is the Delete key below the home key. This is different from the backspace key. Now you are in your bios setup, look for Boot at the top on the menu toolbar. Just use your arrow keys to navigate and your enter/return key to select things. Now under BOOT go to something along the lines of Boot Device Priority. Now make sure that the 1st priority is to boot from a CD rom. Your choices are usually CD Rom, Removable, Hard Disk, or disabled. Make sure the 1st is CD Rom and then you don't have a repeating one after that. So if your 3rd is CD Rom currently, change that to whatever the first is.

After all that is done. Restart again, and it should ask you "Press any key to boot from CD or DVD". So do just that, but do it quick because you only have like 5 seconds before it tries to just boot up normally. Once you do this, it'll load up from your windows CD/DVD rom and there should be a "Repair your windows" option. Try that to fix your .dll and any other issues you might have. If that doesn't work let me know. There are always lots of things you can do.