Vista - Computer wont boot after re-install

I had a problem with my copy of Vista, wouldn't activate because its an upgrade and not full vista??
So I went to re-install XP with the plan to then re-upgrade to Vista, as I installed XP it told me some files were missing.
Now I cant boot up, it starts but then shows 0075 in the bottom right hand corner, which turns to 0078 when everything stops.
I have tried re-setting the CMOS by moving the jumper and also removing the battery but no change!!
Need help please!!!!

Hello Walshandy, and welcome to Vista Forums.

This tutorial will show you how to do a clean install with a upgrade version of Vista so that you are able to activate it afterwards. If you still can activate your Vista after this, then you might try doing a phone activation to see if it will.

Hope this helps,
Shawn

Thanks, but I can't get past the 1st boot up screen it won't even boot from a cd!

You might check the BIOS settings to make sure that you have the CD/DVD drive listed to boot first in the boot order. After you restart, you will only have 8 seconds to press a key, when you see the message, to boot from the Vista installation DVD.