Solved 2 Windows Vistas on one computer

Hi, this is the first time i have used Vista Forums for typing a thread.
I just installed windows vista on my laptop because (i dont know why) a message popped up telling me to insert a cd which i had no clue about.
Anyway, when i the setup for windows vista successfully installed, i restarted my laptop. Once i restarted it, some 2 options came. both of the options were windows vista. I don't know how to remove one of the windows vista from my laptop. Can somebody help me please.
Details:
The options come when i turn my computer on.
They come on a black background on startup.
This problem started when i installed windows vista again on my laptop.
I am normally quite good at fixing computers and i don't even need any help, but this is the first time ever i need help for this issue because it has never occured before.
The 1st windows vista option is the new installation.
The 2nd windows vista option is my old installation which i wanted to overwrite.
I am now always using the 1st option because i cant remove my old installation.
I did not do anything to the 2nd option just incase something goes even worse.
This is the only problem on my laptop. Everything else works in its best performance.
My laptops manufacturer is ACER and the model is ASPIRE 5630
This information is on a sticker on the laptop:
ACER - Aspire 5633WLMi - Intel(R) Core (TM) 2 Duo processor T5500 (1.66 GHz, 667 MHz FSB, 2 MB L2 cache) - 15.4" WXGA Acer CrystalBrite(TM) LCD (16ms) - Intel (R) Graphics Media Accelerator 950 - 80GB HDD - DVD-Super Multi double layer (support DVD+R Double Layer/DVD_RW) - 1GB DDR2 - 802.11a/b/g wireless LAN.

Thanks!

Welcome,

Reinstall using the clean inatall procedure. If you follow the instructions in this tutorial, everything will be fine.

It is very important that you choose clean install and then use the advanced options, when shown to format you drive.

http://www.vistax64.com/tutorials/68767-clean-install-upgrade-vista.html?ltr=C

reformat hdd now!

Thank you so much for the rep and the appreciation. I am glad that my idea worked, and even more glad that you are satisfied. Come back at any time to use our knowledge or to share yours.