http://www.nu2.nu/pebuilder/#legal
QUOTE
When using BartPE you should know that:
1. It is legal to make a "backup copy" of ANY files from your original Windows XP/2003 media to another media.
2. It is legal to add any other files you wish to the backup media.
3. It is not legal to use a BartPE CD and an installed Windows XP/2003 both at the same time under the same Windows XP/2003 EULA.
4. It is not legal to change any binary files in the process according to the Windows XP/2003 EULA. This makes "winlogon" and "bootscreen" hacks illegal.
5. A BartPE image is (and I quote) "not a properly licensed WinPE". This means that if you want to have a licensed WinPE, you cannot use BartPE. However, you can use a BartPE image under the license of the Windows XP/2003 EULA that came with the BartPE XP/2003 source media.
I feel that, considering the above, Microsoft cannot say that BartPE is illegal. If you don't break the rules of (3), (4), (5) and you don't make more than one BartPE CD without having more than one Windows XP/2003 license, you can use it any environment.
The PE Builder download archive does not include any plugins that will break any of the rules show above. But you must be careful with plugins created by others!
I think it's a bit of a grey area, maybe Steel might be able to offer more insight onto the legalities of what you are wanting to do. I suspect that if you use this CD on a licensed XP PC you would be OK, using it on a 9x, 2k PC I think it could be getting into a very murky grey area.
Some software on the CD ie AntiVir you couldn't use as it's for personal use only, there are other's on the CD as well which are just for personal use.
However Trend Micro Sysclean is free for you to use, and you could always add clamwin to the CD.