new install, wubi or dualboot system?

I would say Dual-Boot,

it's faster in reading & writing to the hard drive.

you can read more here: http://wubi-installer.org/faq.php

What is Wubi

Wubi Ubuntu installation
Wubi http://wubi-installer.org/, is a Ubuntu installer for Windows. ( Windows UBuntu Installer ) WUBI
Wubi installer is a good method, but not the best, to install and try Ubuntu for Windows user, using an easy way.
Wubi installer don't make a real ext3 filesystem partition, separated isolated from Windows, it create a big file into the windows filesystem and install Ubuntu in it, so if you have problems into Windows partition (viruses, filesystem corruption) you can damage and loose all the installed Ubuntu.

Ubuntu installation
Boot the pc and install Ubuntu from Ubuntu live install cd, is the usual and best way to install Ubuntu in dual boot mode. (Ubuntu is installed not using Windows)
https://help.ubuntu.com/community/Installation/I386
install Ubuntu 8.04.1 https://help.ubuntu.com/community/GraphicalInstall

If this solves you problem, please mark as Solved. If not, please clarify your question.

Hope this helps

Here some general note on install Ubuntu and howto to get a good ubuntu iso cd image (.iso) to burn on a cd:

- Here the steps to install Ubuntu 10.04 https://help.ubuntu.com/community/GraphicalInstall
- Here a video http://www.youtube.com/watch?v=XaqaDZZ_P0g&feature=fvw

The main ubuntu site is this: www.ubuntu.com and the download location is this
http://www.ubuntu.com/desktop/get-ubuntu/download

Ubuntu prerequisites: https://help.ubuntu.com/community/Installation/SystemRequirements
Ubuntu 10.04 release notes: https://wiki.ubuntu.com/LucidLynx/ReleaseNotes

1) please download the 700 mb file http://www.ubuntu.com/desktop/get-ubuntu/download simply press on download button
To avoid download errors download the desired ubuntu iso install cd image using the torrent protocol.

- if you are using Windows please install a torrent client i suggest you http://deluge-torrent.org/
and download the iso using a .torrent link from here:
http://releases.ubuntu.com/10.04/ubuntu-10.04-desktop-i386.iso.torrent

2) PLEASE BE SURE TO CHECK the md5sum of downloaded file to be sure it have no error https://help.ubuntu.com/community/HowToMD5SUM
Only if the md5sum number match with this: http://releases.ubuntu.com/10.04/MD5SUMS go to the next steps.

3) burn the iso image onto a cd, to do it install and use http://infrarecorder.org/?page_id=5 burn the cd at lower speed you can do and activate the data verify

4) insert the self made install cd into your pc cdrom drive and reboot your pc. YOU MUST NOT SEE Windows starting and you can try Ubuntu from cdrom and then install it

If you have trouble with installation (the system freeze or you can't complete it) be sure to read the above suggestions, then:

1.a ) Please boot entirely (you must not see windows starting) from Ubuntu live install cd and when the system start to boot from cd you will see two bottom screen icons (keyboard and man inside circle ) please press space (choose your desired language) then a screen textual center menu will appear to you with this items in it:

Try Ubuntu without installing
Install Ubuntu
Check disc for defects
Test memory
Boot from first hard disk

Please select "Check disc for defects" and press enter to test if your cd-driver can read in a good way the live install cd... or if the install cd have some defective file in it.
Then please also perform a Test memory to be sure your pc RAM memory have not any issue

If you get a blank screen at boot after install or booting from the Ubuntu install cd please read:

http://www.ubuntugeek.com/how-to-fix-ubuntu-10-04-lts-lucid-blank-screen-at-startup.html

Additionally, if you are new to Ubuntu, i recommend reading through the Ubuntu Manual, it's very informative:

http://ubuntu-manual.org/

Click on the "download Button" to download the latest PDF version.