This question seems to repeat itself through out ever forum I visit. So I thought I'd pass along a few answers to those who do not know how to do so.
These steps are for those who do not have or do not wish to use a Virtual PC or 2nd PC. You will need 25Gb of free and at least 10GB of that should be on drive C:\. If you do not have this, STOP NOW!
Step - 1
Please remember that this is indeed only a BETA (pre-release / not final). It CAN crash your system. Once you accept that, please move to step 2.
Step - 2
Back up all your wanted data. Take a moment and review what you want backed up and and be sure you have done so. Once you are 100% sure, move to step 3.
Step - 3
Extract the ISO using UltraISO or ISO Buster. Of course if you have another program to do this, feel free to use it. WinRar will NOT work.
It would be a good idea to have the extracted file on another drive or partition. However it MUST be on another drive or partition if you plan to replace your current OS.
Step - 4
Decide if you wish to UPGRADE your copy of Windows to Windows Vista or run it along side your current OS.
UPGRADING - Step A
Dual Boot (your OS & VISTA on the same PC) - Step B
Fresh Install (delete everything & have only vista) - Step C
Step - A UPGRADING
If Upgrading, simply click on SETUP.exe within the newly extracted folder and select the upgrade option. Follow all screen prompts. - Your DONE!
Step - B Dual Boot
If you do not want to upgrade, but rather run your current OS side by side... You should ALREADY have your drive partitioned. You CAN NOT run your current OS and Vista on the SAME drive.
Click Setup.EXE within your newly extracted folder and select for a fresh install. Once selected, pick the other drive or partition that is not currently being used. Follow all the on screen prompts.
Once setup, you should be able to pick from Vista and your old OS, every time you boot or reboot your PC. If this does not work for you, please re-read step 1. - Your DONE!
Step C - Windows Vista Only - Fresh Install
The easiest way is order the DVD kit (6.00 shipping cost) or buy a DVD burner and some blank DVD-R's. However, if this is not an option for you....
Re-read Steps 1 & 2. Re-read steps 1 & 2 again.
You will need 3 drives or partition. One of which your extracted file should be on. This folder should NOT be on the partition or drive 1 & 2.
Partition 1 should be BLANK or have data you do not mind deleting.
Partition 2 should have your current OS.
Partition 3 should be ONLY the extracted folder and anything else you do not want DELETED.
This also will not work if your current OS is on drive C:\
Follow Step 2. Follow Step 4B. Again follow Step 2. Format Partition 2, which had your old OS. Remove your old OS from boot.ini or your boot loader.
You can now either merge Partition 2 with 1 or keep your system as is. - Your DONE!