Hey, im wondering how i'd be bale to modify Windows Vista both theme wise and logon... i plan to make a Umbrella Corp theme and log on, can this be done with photoshop?
Depends, There are two systems that come to mind when I think editing windows though : Windowsblinds, Which allows you to edit and construct themes and designs, and then Blackbox, (BB4WIN.com), Blackbox doesn't have a running system on vista as far as I'm aware, but Blackbox is complete open source editing of really whatever you want, Check it out. Also, The only thing about Windows-Blinds is that you have to purchase the full version, I believe they offer a trial. BB~ is completely free.
You can get Logon Studio for Vista, it is free. I haven't gotten my bootscreen to change. You can use Window glazz to use custom themes, but that'll take some learning to be able to create your won. (But as opposed to Windowblinds, it doesn't take up any additional resources). You could also try a full blown shell replacer, I'm not to up to speed on those, let alone ones for Vista.